bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-site immunoradiometric assay for detection of Plasmodium falciparum antigen in blood using monoclonal and polyclonal antibodies
Authors: Khusmith S , Tharavanij S , Kasemsuth R , Vejvongvarn C , Bunnag D
Published: January 2020

Three systems of immunoradiometric assays (IRMAs), a two-site monoclonal antibody sandwich IRMA (MAb-IRMA), two-site polyclonal antibody-monoclonal antibody sandwich IRMA (PAb-MAb-IRMA), and two-site polyclonal antibody sandwich IRMA (PAb-IRMA), were developed to detect low-grade infections with Plasmodium falciparum. The assays showed good correlation with parasitemia when tested against parasites from in vitro cultures (r = 0.996, 0.994, and 0.998 for MAb-, PAb-MAb-, and PAb-IRMA, respectively), with the ability to detect as few as 0.24, 0.67, and 1.82 parasites per 10(7) erythrocytes, respectively. The assays were specific for P. falciparum, since a serially diluted specimen from a patient with vivax malaria with an initial parasitemia of 0.8% and almost all of the undiluted specimens from five other vivax malaria patients were negative. The assays were performed on patients with falciparum malaria before and after treatment with antimalarial drugs. Before treatment, all 24 patients were positive by all three systems of two-site sandwich IRMAs. Two weeks after treatment, 81.8% (18 of 22) of the patients were positive by microscopic examination, but the IRMA positivity rates were 90.9% (20 of 22), 86.4% (19 of 22), and 81.8% (18 of 22) for MAb-, PAb-MAb-, and PAb-IRMA, respectively. Four weeks after treatment, all 19 patients were negative by microscopic examination, but 52.6% (10 of 19) of the patients were still positive with MAb- and PAb-MAb-IRMA and 31.6% (6 of 19) were positive with PAb-IRMA. Comparison between the three systems of IRMA showed that the MAb-IRMA was superior to the other two systems for three reasons. First, it gave a lower count when tested with blood from healthy individuals. Second, it gave a higher count when tested with blood from patients with falciparum malaria. Third, it gave better correlation with parasitemia when blood from falciparum malaria patients was tested. MAb-IRMA is recommended for use for the detection of low-grade P. falciparum infection.
Sensititre autoreader for same-day breakpoint broth microdilution susceptibility testing of members of the family Enterobacteriaceae
Authors: Doern G V , Staneck J L , Needham C , Tubert T
Published: January 2020

The Sensititre Autoreader system is an instrument-assisted broth microdilution susceptibility test procedure based on the detection of fluorogenic growth substrate metabolism by test bacteria with different concentrations of antimicrobial agents. In the current investigation, this system was assessed as a means for predicting the in vitro activity of 17 antimicrobial agents versus numerous species of the family Enterobacteriaceae and Pseudomonas aeruginosa by using a breakpoint broth microdilution test format. Same-day and overnight determinations of susceptibility were made with the Sensititre Autoreader system, and in both cases, the results were compared with those obtained with a manual overnight breakpoint broth microdilution susceptibility test. Among a total of 6,086 organism-antimicrobial agent comparisons with Enterobacteriaceae, concordance was noted between the results of the same-day Autoreader system and the manual overnight test in 94.4% of cases. The same-day Autoreader results with members of the Enterobacteriaceae other than Proteus spp. were determined after 4 h of incubation; with Proteus spp. the same-day Autoreader results were determined after 5 h of incubation. When the Enterobacteriaceae Autoreader results were determined after 18 h of incubation, concordance was noted in 97.2% of comparisons. Among a total of 1,377 organism-antimicrobial agent comparisons with P. aeruginosa after 18 h of incubation, agreement of results from the manual overnight test and the Autoreader system was achieved in 92.2% of cases.
Demonstration and partial characterization of parasite-specific immunoglobulin A responses in human strongyloidiasis
Authors: Genta R M , Frei D F , Linke M J
Published: January 2020

By using an enzyme-linked immunosorbent assay, serum immunoglobulin A (IgA) responses directed against Strongyloides stercoralis larvae antigens were measured in 104 presumably immunocompetent individuals with chronic uncomplicated strongyloidiasis and in 15 immunocompromised patients with S. stercoralis infection. Fifty healthy North American adults and 18 patients with other helminthic parasites served as controls. All 50 healthy controls were negative for antibody responses (mean absorbance +/- standard deviation = 0.0724 +/- 0.040). The mean absorbance of the 18 parasitized controls was 0.230 +/- 0.087; two individuals parasitized by Ascaris lumbricoides showed positive antibody responses. The mean absorbance of the immunocompetent patients with strongyloidiasis was 0.680 +/- 0.364, with 91 subjects (87.5%) having a positive value (greater than 0.300). Of the immunocompromised patients (mean absorbance +/- standard deviation = 0.735 +/- 0.538), 11 (73%) had a positive antibody response test. When the IgA responses of these two groups were compared, they were not significantly different. There was no correlation between the levels of total serum IgA and the concentration of specific IgA in the infected patients. Both IgA and IgG immunoreactive bands were detected on immunoblots of sodium dodecyl sulfate-polyacrylamide gel electrophoresis-separated larval antigen protein blots. Nineteen bands were recognized by IgG, and 13 were recognized by IgA from sera of infected patients. Several bands displayed specific IgG or IgA reactivity. The present work shows that most patients with strongyloidiasis mount specific IgA responses against filariform larval antigens. These responses are, for the most part, directed against antigens that are different from those recognized by IgG. The lack of correlation between the magnitude of the specific serum IgA responses and the clinical aspects of the infection suggests that these antibodies may not play a central role in the regulation of this parasitosis.
HeLa cell adherence and cytotoxin production by enteropathogenic Escherichia coli isolated from infants with diarrhea in Thailand
Authors: Echeverria P , Taylor D N , Donohue-Rolfe A , Supawat K , Ratchtrachenchai O , Kaper J , Keusch G T
Published: January 2020

Enteropathogenic Escherichia coli (EPEC) strains isolated from hospitalized infants with diarrhea in Thailand were examined for HeLa cell adherence and cytotoxin production. Of 101 strains examined, 56 adhered to HeLa cells in a localized pattern (LA), 27 adhered in a diffuse pattern (DA), and 18 did not adhere. All 56 LA EPEC strains were O:K serotype O119:K69. A total of 20 (83%) of 24 EPEC O86:K61 strains and 7 (38%) of 19 EPEC strains belonging to six other O:K serotypes exhibited DA. All LA EPEC strains hybridized with a DNA probe for genes encoding EPEC adherence factor, whereas none of the 27 DA or 18 nonadherent EPEC strains hybridized with EPEC adherence factor probe. Sonic extracts of 57 (58%) of 98 EPEC strains tested at a dilution of 1:100 caused greater than 25% mortality of HeLa cell monolayers. A total of 50 (88%) of 57 cytotoxic sonic extracts were inhibited to various degrees by a 1:500 dilution of polyclonal rabbit antisera to purified Shiga toxin. The mean percent inhibition of cytotoxic sonic extracts by anti-Shiga toxin was 67% (range, 29 to 89%). Fifty percent (38 of 56) of LA EPEC strains, fifty-two percent (14 of 27) of DA EPEC strains, and fifty-three percent (8 of 15) of nonadherent EPEC strains produced Shiga-like toxins. Both adherence and low levels of cell-associated cytotoxins were identified in EPEC strains from Thailand, but there did not appear to be an association between these two factors.
Organism resembling Neisseria gonorrhoeae and Neisseria meningitidis
Authors: Hodge D S , Ashton F E , Terro R , Ali A S
Published: January 2020

A problem isolate resembling Neisseria gonorrhoeae and Neisseria meningitidis is reported. Growth and biochemical characteristics indicated the organism to be N. meningitidis, whereas serological characteristics indicated it to be N. gonorrhoeae. This vaginal isolate may be a genetically transformed gonococcus with the ability to utilize maltose. Conversely, it may be a meningococcus which has acquired antigenic determinants of N. gonorrhoeae.
Production and use of a hemagglutinin for detecting antibody to Jamestown Canyon virus
Authors: Grimstad P R , Artsob H , Karabatsos N , Calisher C H
Published: January 2020

A procedure was developed for producing a hemagglutinin for the California serogroup (family Bunyaviridae, genus Bunyavirus) virus Jamestown Canyon, a human pathogen. Serum samples from humans putatively infected with this virus or with La Crosse virus were tested by hemagglutination inhibition. Each antigen detected antibody to the respective virus, with little cross-reactivity. These results suggest that both antigens should be used when the hemagglutination inhibition test is applied to the diagnosis of human infections with California serogroup viruses in North America.
Serratia plymuthica sepsis associated with infection of central venous catheter
Authors: Horowitz H W , Nadelman R B , Van Horn K G , Weekes S E , Goyburu L , Wormser G P
Published: January 2020

Serratia plymuthica was isolated from the blood and from a central venous catheter tip in a 54-year-old man with alcoholic cirrhosis and clinical signs of sepsis. This was the seventh reported isolate of S. plymuthica from a clinical specimen and the first in which the organism was clearly a significant pathogen.
Seasonal prevalence of Borrelia burgdorferi in natural populations of white-footed mice, Peromyscus leucopus
Authors: Anderson J F , Johnson R C , Magnarelli L A
Published: January 2020

Borrelia burgdorferi, the etiologic agent of Lyme disease, was isolated from 111 of 237 Peromyscus leucopus captured during all seasons of the year. Borreliae were cultured from tissues of the spleen (101 mice), left kidney (76 mice), and right kidney (73 mice), from blood (12 mice), and from one fetus. Mice were infected during the winter, when immature Ixodes dammini were inactive. The prevalence of infection during the winter (less than or equal to 33%) was more than twofold lower than that during the summer (ca. 75%), a time when nymphal ticks are abundant. Overwintering, infected mice are reservoir hosts for subadult ticks that begin feeding in early spring. Twenty white-footed mice from which B. burgdorferi was isolated from tissues of spleen or kidney but not from blood were parasitized by larval I. dammini or Dermacentor variabilis which harbored borreliae. We conclude that these mice were infectious to feeding ticks, even though borreliae were not isolated from blood.
Influence of lysozyme on aggregation of Staphylococcus aureus
Authors: Millar M R , Inglis T
Published: January 2020

The conditions under which lysozyme aggregates Staphylococcus aureus were studied. Lysozyme was found to aggregate S. aureus at concentrations found in human tear secretions. Aggregate size depended upon lysozyme concentration, ionic strength, and bacterial concentration. There was a low level of adherence of S. aureus to corneal epithelial cells, and the adherence of a recent clinical isolate was not influenced by lysozyme concentrations found in human tear secretions. Lysozyme may enhance bacterial clearance from the corneal surface of the eye by promoting particle aggregation.
Cultivation and characterization of rotavirus strains infecting newborn babies in Melbourne, Australia, from 1975 to 1979
Authors: Albert M J , Unicomb L E , Barnes G L , Bishop R F
Published: January 2020

Twenty-three rotavirus strains obtained from the stools of 71 newborn babies were adapted to growth in MA-104 cells. Babies were housed in newborn nurseries of eight different obstetric hospitals in Melbourne between 1975 and 1979. All strains belonged to serotype 3 when reacted with serotype-specific neutralizing monoclonal antibodies in an enzyme immunoassay. Genome RNA of these 23 strains and of one stool virus not adapted to cell culture were compared by coelectrophoresis of mixtures of RNA. When strains were compared by coelectrophoresis of RNA for 4 h at 40 mA current, the majority appeared to be identical. Coelectrophoresis at 4 degrees C for 17 h at 10 mA current with 0.75-mm-thick polyacrylamide gels resulted in increased resolution of segments, revealing more genetic diversity than previously observed. Seventeen different electropherotypes showing slight variations in migration of one to seven segments were identified. Segments 5 and 7, 8, 9, 10, and 11 varied more frequently than segments 1, 2, 3, 4, and 6. Strains endemic in one hospital from 1975 to 1983 showed increased numbers of segmental changes over time. Differing patterns of reaction with two neutralizing monoclonal antibodies reacting with VP3 and VP7 were observed. Comparison of electropherotypes of three neonatal strains with a serotype 3 community strain showed marked differences in segment migration. The serotypic similarity, electropherotypic dissimilarity from community strains, and asymptomatic nature of most infections are additional evidence that these viruses infecting newborn babies form a unique group of rotaviruses.
Murine monoclonal antibodies for detection of antigens and culture identification of Neisseria meningitidis group B and Escherichia coli K-1
Authors: Krambovitis E , McIllmurray M B , Lock P A , Holzel H , Lifely M R , Moreno C
Published: January 2020

Four murine monoclonal antibodies which reacted with a (2----8)alpha-linked sialic acid polysaccharide were produced. Three of the antibodies reacted specifically with Neisseria meningitidis serogroup B and Escherichia coli K-1 polysaccharide antigens, whereas one antibody cross-reacted with N. meningitidis group C polysaccharide antigen, a (2----9)alpha-linked homopolymer of sialic acid. By using the most avid antibody (MB 62), a latex particle agglutination test was developed which could detect capsular polysaccharide at 10 ng/ml. It also detected antigen in the cerebrospinal fluid (CSF) of all seven N. meningitidis group B- and two E. coli K-1-infected patients, whereas 57 control CSF samples, including 8 from neonates, were negative. Cultures of 21 N. meningitidis group B strains, 7 E. coli K-1 strains, and 1 Moraxella nonliquefaciens strain gave a positive result, whereas 53 strains from other serogroups were all negative. In a separate clinical evaluation, the overall sensitivity of the latex particle agglutination test was 81% (22 of 27) with fresh CSF samples, 48% (15 of 31) with stored CSF samples, and 94% (32 of 34) with blood cultures. No false-positive reactions were recorded with 165 control CSF samples, and the specificity with blood cultures was 99.4% (519 of 522).
Hydrolytic enzymes of "Streptococcus milleri"
Authors: Ruoff K L , Ferraro M J
Published: January 2020

Seventy-two isolates classified as "Streptococcus milleri" were examined for the presence of various hydrolytic enzymes. While no protein or lipid-degrading activities were demonstrated, some isolates showed DNase and mucopolysaccharide-degrading activities. Beta-hemolytic isolates were more likely to produce these enzymes than were nonhemolytic strains. Isolates of one "S. milleri" biotype (mannitol fermentation positive) were uniformly devoid of all enzyme activities tested.
Detection of culture-derived Babesia bovis exoantigen using a two-site enzyme immunoassay
Authors: Montealegre F , Montenegro-James S , Kakoma I , Ristic M
Published: January 2020

Soluble exoantigens in the supernatants of Babesia bovis cultures have been shown to be efficient immunogens against bovine babesiosis. We used a two-site enzyme immunoassay to monitor the release of these antigens during in vitro cultivation. Bovine immunoglobulin G was isolated from serum of an adult cow previously immunized with culture-derived B. bovis exoantigens and challenged via needle with virulent parasites. The specific immunoglobulin G was used as a capture antibody and as an enzyme-conjugated recognizing antibody. The optimal protein concentration of capture antibody was 10 micrograms/ml. The 24-h cultures showed the greatest antigen concentration. The test was sensitive for detection of differences in species-specific antigenic activity among B. bovis isolates, for determining loss of antigenicity during storage and formalinization, and for monitoring the kinetics of exoantigen release during in vitro cultivation. Antigens cross-reactive with the other major Babesia species of cattle, Babesia bigemina, were also detected with this assay. The high specificity, sensitivity, and reproducibility of this technique should facilitate detection and quantitation of Babesia antigens during purification and in standardization of candidate immunogens.
Comparison of monoclonal time-resolved fluoroimmunoassay with monoclonal capture-biotinylated detector enzyme immunoassay for adenovirus antigen detection
Authors: Hierholzer J C , Johansson K H , Anderson L J , Tsou C J , Halonen P E
Published: January 2020

A sensitive time-resolved fluoroimmunoassay (TR-FIA), adapted from TR-FIA procedures already described, was developed with monoclonal antibodies and compared with several enzyme immunoassays (EIAs) for detecting adenovirus antigens in clinical specimens. The most sensitive EIA was an all-monoclonal assay with biotin-labeled detector antibody and streptavidin-peroxidase conjugate. All tests were evaluated with nasopharyngeal aspirate specimens from respiratory illness, with tissue homogenates from patients with systemic infection, and with stool specimens from gastrointestinal illnesses. For respiratory and tissue specimens, the TR-FIA detected adenovirus in 85% of the specimens positive by culture, which was a sensitivity similar to those of the all-monoclonal biotin-avidin EIA (79%) and the polyclonal-capture biotin-avidin EIA (88%). For stool specimens, the TR-FIA detected adenovirus in 100% of the specimens positive by culture, which was a decidedly higher sensitivity than either EIA format (78 and 75%, respectively). The TR-FIA was shown to be an efficient, flexible, and specific test for large numbers of clinical specimens.
Rapid identification of Campylobacter pylori (C. pyloridis) by preformed enzymes
Authors: McNulty C A , Dent J C
Published: January 2020

Campylobacter pylori (C. pyloridis) is a fastidious organism found in the gastric mucosa associated with histological gastritis and peptic ulceration. A rapid identification scheme that detects the presence of preformed enzymes (Rosco Diagnostica, Taastrup, Denmark) was applied to clinical isolates of C. pylori. The isolates tested were a very homogeneous group. They all produced oxidase, catalase, urease, alkaline phosphatase, gamma-glutamyl aminopeptidase, leucine aminopeptidase, and DNase. None produced any of 44 other enzymes tested. No other campylobacter strains produced gamma-glutamyl aminopeptidase, except the six strains of Campylobacter jejuni biotype 2. Different results were obtained with similar substrates produced by other manufacturers, probably due to small substrate differences. These tests are useful for the rapid identification of C. pylori but would be unhelpful in any biotyping scheme. They can also be used to help differentiate other groups within the genus Campylobacter.
Intrinsic catalase dot blot immunoassay for identification of Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium intracellulare
Authors: Wayne L G , Diaz G A
Published: January 2020

The heat-labile T class of mycobacterial catalase exhibits peroxidase activity with some substrates. Most species of mycobacteria produce T-catalase, which is serologically characterized by a combination of shared epitopes and unique, species-specific epitopes. Antibodies to T-catalases from Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium intracellulare have been cross absorbed with T-catalases from heterologous species and applied as dots to nitrocellulose membranes. When these membranes were incubated with crude sonic extracts of 93 strains of mycobacteria that produce sufficient T-catalase, and were then exposed to 3,3'-diaminobenzidine peroxidase substrate, only those extracts made from one of the three species represented yielded a discrete brown dot at the site of the corresponding globulin. The sensitivity of the test was at least 96.5%, and the specificity was in excess of 99.5%.
In vitro antimicrobial spectrum, occurrence of synergy, and recommendations for dilution susceptibility testing concentrations of the cefoperazone-sulbactam combination
Authors: Jones R N , Barry A L , Packer R R , Gregory W W , Thornsberry C
Published: January 2020

Broth microdilution tests and an antimicrobial interaction (synergy) studies using various combinations of cefoperazone and sulbactam were performed in an effort to determine the most appropriate in vitro dilution test system. The test results with cefoperazone and sulbactam were categorized as synergistic (complete or partial) for nearly 80% of the strains isolated from clinical trial patients. The results indicate that the cefoperazone-sulbactam fixed ratio (2:1) maximized the cefoperazone spectrum of activity and best approximated the parenteral formulation of the drug. The cefoperazone-sulbactam combination had a greater antimicrobial activity than did the other comparison beta-lactams, except for imipenem, tested against strains of the family Enterobacteriaceae. To be consistent with the National Committee for Clinical Laboratory Standards interpretive breakpoints for cefoperazone alone, the following MIC breakpoints should be applied to the combination (2:1 ratio): less than or equal to 16/8 micrograms/ml, susceptible; 32/16 micrograms/ml, moderately susceptible; and greater than or equal to 64/32 micrograms/ml, resistant.
Selective and differential medium for recovery of Pseudomonas cepacia from the respiratory tracts of patients with cystic fibrosis
Authors: Welch D F , Muszynski M J , Pai C H , Marcon M J , Hribar M M , Gilligan P H , Matsen J M , Ahlin P A , Hilman B C , Chartrand S A
Published: January 2020

A selective and differential medium, OFPBL (oxidation-fermentation base supplemented with agar, lactose, and two antimicrobial agents), for the isolation of Pseudomonas cepacia from respiratory specimens of patients with cystic fibrosis was developed and tested. Among 725 specimens submitted from seven centers over a 4- to 6-month period, 58 (8%) yielded P. cepacia on OFPBL; only 19 of these were recovered on MacConkey or sheep blood agar (P less than 0.001). No isolate was recovered on MacConkey or sheep blood agar alone. Ranges of recovery rates among centers were 0 to 15% on OFPBL and 0 to 10% on MacConkey or sheep blood agar. Ninety percent of P. cepacia isolates were detected on OFPBL in less than or equal to 3 days. Other nonfermenters and yeasts isolated on OFPBL were distinguished from P. cepacia by failure to acidify the medium. The new medium was clearly superior to MacConkey and sheep blood agars for the isolation of P. cepacia from the respiratory secretions of patients with cystic fibrosis.
Induction and measurement of 2',5'-oligoadenylate synthetase in Madin-Darby bovine kidney cells and in cattle
Authors: Short E C , Fulton R W
Published: January 2020

2',5'-Oligoadenylate [2',5'-oligo(A)] was separated from 14C-labeled nucleosides produced in the 2',5'-oligo(A) synthetase assay by using 100-microliters columns of Dowex 1. No detectable nucleoside remained on the column after elution with 20 column volumes of water, whereas less than 1% of oligonucleotides were eluted from the column. At least 99% of oligonucleotides were eluted from the column with 1 M NaCl, pH 2. The major product had properties consistent with 2',5'-oligo(A). Exposure to alpha-1 bovine interferon (IFN) caused an increase in cellular 2',5'-oligo(A) synthetase activity which was proportional to the concentration of IFN in the medium up to 10(4) U of IFN per ml and then leveled off at about 15 X control activity. Under the assay conditions used, 2',5'-oligo(A) synthetase activity was directly proportional to the amount of cell extract over a 10-fold range. Cattle inoculated with IBR/BVD/PI-3 modified live virus vaccine showed an increase in 2',5'-oligo(A) synthetase activity in peripheral blood mononuclear leukocytes which persisted for at least 3 days postvaccination. Intramuscular injection of cattle with IFN caused a similar increase in 2',5'-oligo(A) synthetase activity. Changes in 2',5'-oligo(A) synthetase activity should be of value in (i) assessing the response of cattle to experimental viral infections or inoculations with viral vaccines or IFN or (ii) indicating a possible viral etiology in disease.
Determination of hippurate hydrolysis by gas-liquid chromatography
Authors: Wallace P L , Patton C M , Moss C W
Published: January 2020

A rapid gas-liquid chromatographic procedure was developed to determine hippurate hydrolysis by microorganisms. Bacterial cells were inoculated into 0.4 ml of 1% sodium hippurate and incubated for 2 h at 37 degrees C. Cells were removed by centrifugation, and the benzoate released by enzyme activity was converted to methyl benzoate and analyzed by gas-liquid chromatography. This procedure is sensitive, and its specificity provides a high degree of reliability for organisms with weak hippuricase activity.
Association of Malassezia pachydermatis with systemic infections of humans
Authors: Gueho E , Simmons R B , Pruitt W R , Meyer S A , Ahearn D G
Published: January 2020

Thirty-two Malassezia spp. isolates from human clinical specimens represented M. furfur and M. pachydermatis. Both species reportedly were obtained from patients with similar febrile systemic syndromes, including infections of the lungs or other tissues.
Gastroenteritis, sepsis, and osteomyelitis caused by Plesiomonas shigelloides in an immunocompetent host: case report and review of the literature
Authors: Ingram C W , Morrison A J , Levitz R E
Published: January 2020

We report the 11th human case of bloodstream infection with Plesiomonas shigelloides. This was the first case without any apparent underlying immunocompromising disease, and the patient was the first adult to survive the infection. We review all the extraintestinal cases associated with this organism, giving special attention to the clinical characteristics of the bloodstream infections reported previously.
Sources of rats free of latent Pneumocystis carinii
Authors: Bartlett M S , Durkin M M , Jay M A , Queener S F , Smith J W
Published: January 2020

Two sources of rats free of latent Pneumocystis carinii are described. First, rats from a virus-free colony failed to develop infection after 8 weeks of immune suppression unless they were housed with previously infected rats. Second, pregnant rats (non-virus free) received trimethoprim-sulfamethoxazole from day 10 of gestation until the pups were weaned. Pups raised in filter-topped cages and immunosuppressed for 8 weeks were free of P. carinii infection.
Evaluation of a latex test for rotavirus detection
Authors: Brandt C D , Arndt C W , Evans G L , Kim H W , Stallings E P , Rodriguez W J , Parrott R H
Published: January 2020

A latex agglutination (LA) test (Slidex Rota-Kit; bioMérieux, Marcy-l'Etoile, France) was a rapid, easily used method for detecting rotavirus (RV) in pediatric fecal specimens. With 45 RV-positive and 50 RV-negative diarrhea specimens, the sensitivity of the LA test was 82%, and the specificity was 100%. Six other specimens produced indeterminate results. The frequency of positive LA tests appeared to be proportional to the concentration of virions in the stool.
Characterization of an unclassified microaerophilic bacterium associated with gastroenteritis
Authors: Archer J R , Romero S , Ritchie A E , Hamacher M E , Steiner B M , Bryner J H , Schell R F
Published: January 2020

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.
Antibodies to cysts of Giardia lamblia in primary giardiasis and in the absence of giardiasis
Authors: Jokipii L , Miettinen A , Jokipii A M
Published: January 2020

The significance of serum antibodies binding to cysts of Giardia lamblia was evaluated by indirect immunofluorescence. Titers of 10 or higher were found in 85.6% of adults, who had probably never had giardiasis. Titers in 118 adults (geometric mean, 29.9) were higher than in 35 children (16.4), and titers in women (42.3) were higher than in men (20.0). Titers in 150 patients with primary giardiasis (80.4) were higher than in control adults, but overlapping precluded serological diagnosis. Titers increased with the duration of infection. Female patients had higher titers (100.5) than did males (66.1), but men who had been infected longer than 45 days had high titers (132). Titers in second serum samples taken from 26 patients 2 weeks to 3 months after successful nitroimidazole treatment (58.1) were lower than before treatment (151.7) but higher than in 118 controls. We conclude that most people have antibodies which cross-react with G. lamblia but which are induced by other immunogens and that primary giardiasis induces protracted systemic antibody responses.
Detection of antibody to cytomegalovirus-induced early antigens and comparison with four serologic assays and presence of viruria in blood donors
Authors: Lentz E B , Dock N L , McMahon C A , Fiesthumel S R , Arnold C B , Lamberson H V
Published: January 2020

Five hundred blood donors were evaluated for cytomegalovirus (CMV) viruria, antibody to CMV early antigens (EA-ab), CMV seropositivity by two screening assays, and CMV-specific immunoglobulin M by two methods. Three donors were viruric, EA-ab positive, and seropositive; two viruric donors were immunoglobulin M positive.
Survival of bacteria in Difco CultureSwab and Marion Culturette II transport systems
Authors: Appelbaum P C , Spangler S K , Crist R , Crist A E
Published: January 2020

The effects of the CultureSwab (Difco Laboratories, Detroit, Mich.) and Culturette II (Marion Scientific, Div. Marion Laboratories, Inc., Kansas City, Mo.) transport systems on the viability of 95 clinically significant bacteria were studied. Organisms included staphylococci (8 isolates), streptococci (22 isolates), Haemophilus spp. (16 isolates), members of the family Neisseriaceae (14 isolates), Bordetella spp. (5 isolates), members of the family Enterobacteriaceae (16 isolates) and pseudomonads (14 isolates). Viability counts with both methods usually dropped by greater than or equal to 90% after incubation at room temperature for periods ranging from 4 to 48 h, and statistically significant differences between the two methods were not observed. However, counts were generally higher with the Difco method, and this difference may be clinically important.
Quantitation of indirect sandwich enzyme-linked immunosorbent assay parameters
Authors: Chalquest R R
Published: January 2020

The optimization of data from the indirect sandwich enzyme-linked immunosorbent assay has been commonly accomplished by linear regression analysis, even though the data are often essentially sigmoid. A new microcomputer software program (LISACRV) that uses a nonlinear regression statistical model to analyze the data from enzyme-linked immunosorbent assay titration experiments was developed.
Effects of amines and polyamines on turbidimetric and lysoplate assays for lysozyme
Authors: Jenzano J W , Lundblad R L
Published: January 2020

The lysoplate and turbidimetric assays have often been used to measure lysozyme in biological fluids, such as blood and saliva. When the same purified lysozyme standard is used in both assays, results obtained with the lysoplate assay are much higher than those obtained for the same sample in the turbidimetric assay. It is likely, therefore, that other components in the biological fluid sample influence the expression of lysozyme activity in one or both assays to produce such divergent results. Certain amines or polyamines are found in various biological fluids and have the potential to influence the reactions in these two assay systems. It was the purpose of this study to incorporate selected amines and polyamines into purified lysozyme preparations and saliva or into the assay preparations to compare their effects on observed lysozyme activity between the two assay systems. Results showed that when the amine or polyamine was included in the purified sample, lysozyme activity was considerably greater than that of controls in the lysoplate assay, whereas a negligible effect was observed in the turbidimetric assay. If the amine or polyamine was incorporated into the assay preparation, results were more dramatic, with large increases in activity in the lysoplate assay and concomitant inhibition in the turbidimetric assay. Similar effects were observed in the assay of lysozyme in saliva, suggesting a potential mechanism by which the two assay systems produce markedly different results for the same sample.
Evaluation of the campyslide agglutination test for confirmatory identification of selected Campylobacter species
Authors: Hodinka R L , Gilligan P H
Published: January 2020

The utility of a rapid latex slide agglutination test (Campyslide; BBL Microbiology Systems, Cockeysville, Md.) in detecting selected Campylobacter spp. was evaluated and compared with that of conventional identification methods. Isolated colonies suggestive of Campylobacter spp. were tested directly from primary selective media after incubation at 42 degrees C under microaerophilic conditions. Stock cultures of Campylobacter jejuni (n = 27) and C. coli (n = 3) were correctly confirmed to the genus level by latex agglutination when tested in pure cultures or isolated from seeded human feces. A total of 50 fresh clinical isolates of Campylobacter spp. (45 C. jejuni and 5 C. coli) were examined, with complete agreement observed between the latex test and conventional methods. Of 173 non-Campylobacter isolates tested from primary plates, only 1 rough strain of Pseudomonas aeruginosa produced a false-positive result. Although the manufacturer recommends a 30-min antigen extraction, 1 or 5 min was found to be sufficient. Also, confirmation could be achieved within 24 h of inoculation of clinical specimens, 2 days earlier than with conventional methods.
Enzyme-linked immunosorbent assay for quantitation of attachment and ingestion stages of bacterial phagocytosis
Authors: Athamna A , Ofek I
Published: January 2020

Research on phagocytosis of bacteria is often hampered by the inability to distinguish quantitatively between bacteria that have been ingested by phagocytic cells and those which are attached to the surface of the cells. A method using the enzyme-linked immunosorbent assay technique to simply and accurately measure the rate of bacterial ingestion by phagocytic cells is described. The method is based on the ability of antibacterial antibodies to bind to bacteria attached to but not internalized by phagocytic cells. The attached bacteria were quantitated by enzyme-linked immunosorbent assay. Compared with the number of bacteria at zero time (17 bacteria attached per phagocyte) only 10 to 20% of the bacteria remained attached to phagocytic cells after incubation for 30 min at 37 degrees C. The decrease in detected attached bacteria at 37 degrees C was due to internalization of the bacteria by phagocytic cells, since upon disruption of the monolayer, most of the ingested bacteria were recovered, and at 4 degrees C, most of the bacteria remained extracellularly attached. The proposed attachment and ingestion assay is easy to perform, allows the detection of specific attachment of test bacteria, and provides objective quantitation of attached and ingested bacteria. Most importantly, the assay allows testing of ingestion rates of bacteria under many variables on the same day.
Purification, partial characterization, and seroreactivity of a genuswide 60-kilodalton Legionella protein antigen
Authors: Pau C P , Plikaytis B B , Carlone G M , Warner I M
Published: January 2020

A genuswide protein antigen extracted from Legionella pneumophila serogroup 1 (strain Philadelphia 1) cells was enriched by differential pelleting and ammonium sulfate precipitation and subsequently purified with a combination of high-performance size-exclusion and ion-exchange chromatography. The protein has an apparent molecular weight of 650,000 before and 63,000 after urea (5 M) treatment, as determined by size-exclusion chromatography. These proteins resolved to a single band of 60,000 after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The urea-treated protein had an isoelectric point of 5.8. This purified 60-kilodalton protein reacted with a convalescent-phase serum sample from a patient with legionellosis and rabbit immune sera prepared against each of 23 Legionella species. The 60-kilodalton protein may be useful in developing diagnostic tests for legionellosis.
Biotyping coagulase-negative staphylococci
Authors: Hébert G A , Cooksey R C , Clark N C , Hill B C , Jarvis W R , Thornsberry C
Published: January 2020

The biochemical profiles obtained with Staph-Ident (Analytab Products, Plainview, N.Y.) panels were combined with the results of adherence and synergistic hemolysis tests to define biotypes among 1,064 clinical isolates representing eight species of coagulase-negative staphylococci. The 672 isolates of Staphylococcus epidermidis were aligned in 69 of 144 potential biotypes in our scheme because of 18 different biochemical profiles and the eight physiologic subtypes. Isolates of most other species were in fewer biotypes because of more uniform adherence and synergistic hemolysis data, as well as fewer biochemical profiles. Since adherence and synergistic hemolysis may prove to be related to virulence and pathogenicity, biotyping with these test results would help evaluate the reliability of adherence and synergistic hemolysis as possible indices of the clinical significance of some of these organisms. When the antimicrobial susceptibility and plasmid profiles obtained on two clusters of S. epidermidis isolates were compared with the biotyping results, one cluster was not further differentiated by plasmid profiles, but was by antimicrobial profiles; the other cluster with only two biotypes was further divided into five distinct types by plasmid profiles but was not separated at all by antimicrobial profiles.
Coagglutination of Vibrio cholerae, Vibrio mimicus, and Vibrio vulnificus with anti-flagellar monoclonal antibody
Authors: Simonson J G , Siebeling R J
Published: January 2020

Monoclonal antibodies (MAbs) with serological activity for purified flagellar (H) core protein prepared from Vibrio cholerae were identified by enzyme-linked immunosorbent assay. Four of these MAbs reacted with the flagella of V. cholerae and V. mimicus exclusively, while eight MAbs reacted with at least 1 of 30 heterologous Vibrio species tested by enzyme-linked immunosorbent assay or coagglutination. It appears that V. cholerae and V. mimicus express similar, if not identical, H determinants unique to these two Vibrio species. Staphylococcus aureus cells or latex beads armed with the four species-specific MAbs coagglutinated each of 47 isolates identified bacteriologically as V. cholerae or V. mimicus from among 103 Vibrio isolates tested. One coagglutination reagent armed with anti-V. vulnificus H MAb exhibited species specificity in that only V. vulnificus cells were coagglutinated from among the 31 Vibrio species examined. This reagent coagglutinated 20 isolates identified bacteriologically as V. vulnificus in a serological survey. MAb coagglutination reagents offer a rapid, specific, and economical alternative to the classical bacteriological approach to identify the human pathogens V. cholerae, V. mimicus, and V. vulnificus.
Isolation and characterization of mutant strains of Bordetella bronchiseptica lacking dermonecrotic toxin-producing ability
Authors: Nagano H , Nakai T , Horiguchi Y , Kume K
Published: January 2020

Mutant strains of Bordetella bronchiseptica, named B-42, B-76, B-84, and B-119, were obtained after serial passages of a parent strain, L3, on Bordet-Gengou agar plates containing 20% horse blood and 200 micrograms of nalidixic acid per ml (BGN-20 agar plates) at 42 degrees C. Mutant strains completely lacked dermonecrotic toxin-producing ability, and lethal activity of the strains for mice was apparently reduced compared with that of strain L3. Mutant strains were able to grow at 42 degrees C, and the strains were nalidixic acid resistant. The mutant strains showed domed (Dom+) colony morphology with smooth texture (Scs+) and no production of zone of hemolysis (Hly-), but the agglutinability of these strains to antiserum prepared with Dom+ Scs+ Hly+ organisms of strain L3 was the same as that of strain L3. When strain B-42 was inoculated intramuscularly or intranasally into guinea pigs, all the animals survived without manifesting clinical signs and produced a high-level of serum agglutination antibodies against strain L3. These inoculated animals were protected against intranasal challenge with strain L3. These properties of mutant strains are hereditarily stable after 50 subcultures on BGN-20 agar plates or 20 passages in mice. These data suggest that the mutant strains lacking dermonecrotic toxin-producing ability can be used as a live attenuated vaccine against swine atrophic rhinitis.
Herpes simplex virus detection by macroscopic reading after overnight incubation and immunoperoxidase staining
Authors: Ziegler T , Waris M , Rautiainen M , Arstila P
Published: January 2020

Human diploid foreskin fibroblast cells grown in 24-well plates were inoculated with clinical specimens by centrifugation at 1,000 X g for 45 min. Cultures were incubated at 37 degrees C overnight, fixed, and stained with peroxidase-labeled monoclonal antibodies against herpes simplex virus types 1 and 2. Stained plaques of infected cells were large enough to be detected with the naked eye, and microscopic examination did not reveal any further positive specimens. The method was compared with standard isolation in human fibroblasts grown in shell vials and inoculated by centrifugation at 4,000 X g, observed microscopically for the occurrence of typical cytopathogenic effect three times a week for 10 days, and then typed by enzyme immunoassay. Of the 289 specimens tested, 105 were positive and 174 were negative by both methods. Six specimens were positive by standard isolation only, two of them containing varicella-zoster virus, and two specimens were stored frozen before being tested by immunoperoxidase staining. Two specimens found negative by standard isolation were positive by immunoperoxidase staining. For two specimens negative by immunoperoxidase staining, the standard isolation cultures were lost due to microbial contamination. Forty-two specimens found positive by standard isolation were clearly positive when stained only 8 h after inoculation. By standard isolation, positive results were reported on the average 3 to 4 days after inoculation, whereas by immunoperoxidase staining the result was available within less than 24 h. Immunoperoxidase staining of infected cells is a sensitive method for rapid laboratory diagnosis of herpes simplex virus infections, and 24-well plates are convenient for the handling of a large number of specimens.
Detection of cytomegalovirus from blood leukocytes separated by sepracell-MN and Ficoll-Paque/Macrodex methods
Authors: Paya C V , Wold A D , Smith T F
Published: January 2020

Two density gradient separation techniques for separation of blood leukocytes were compared for the laboratory diagnosis of cytomegalovirus (CMV) viremia. Of 510 blood specimens processed by both methods, 76 (14.9%) yielded CMV. Of the 76 positive specimens, 66 (87%) and 65 (86%) were processed by the Ficoll-Paque/Macrodex (F-P/M; Macrodex is dextran 70 in normal saline; Pharmacia, Pisataway, N.J.) and Sepracell-MN methods, respectively. Of the 76 CMV-positive blood specimens, 72 (95%) were detected in shell vial cell cultures, whereas only 42 (55%) were detected in conventional tube cell cultures. The time for recognition of specific cytopathic effects due to CMV in tube cell cultures (8.0 versus 7.1 days), the number of fluorescent foci in each positive shell vial culture (19.3 versus 20.1), and the costs of the reagents ($3.50 versus $2.80) were similar and independent of the leukocyte separation method (F-P/M versus Sepracell-MN). Recovery of CMV from heparinized blood (F-P/M method) was similar to that from EDTA-anticoagulated blood (Sepracell-MN method). The Sepracell-MN method is a rapid and sensitive method for detection of CMV from blood specimens and is recommended as a replacement for the more tedious and time-consuming F-P/M procedure.
Determination of antibody response to influenza virus surface glycoproteins by kinetic enzyme-linked immunosorbent assay
Authors: Snyder M H , Banks S , Murphy B R
Published: January 2020

We modified an existing enzyme-linked immunosorbent assay (ELISA) to be able to use new spectrophotometers which can measure the rate of color development in microtiter wells. This new kinetic-based ELISA (KELISA) required only a single dilution of specimen rather than the multiple dilutions required with endpoint ELISA. In addition, 10- to 100-fold-less specimen was required to perform the KELISA than the ELISA. The level of serum or nasal wash antibody against surface glycoproteins of influenza A or influenza B viruses determined by KELISA was reproducible and correlated highly with the results of endpoint ELISA or hemagglutination inhibition tests. The difference between the KELISA rates, which indicated than an antibody response to infection had occurred, was defined and was analogous to a 2.2-fold rise in titer for serum and a 3.4-fold rise in titer for nasal wash determined by endpoint ELISA. The KELISA was similar to endpoint ELISAs in its ability to detect rises in antibody level in paired serum or nasal wash specimens obtained from volunteers who received live attenuated influenza A reassortant virus vaccines. By eliminating the need for multiple dilutions, the use of KELISA offers the advantage of increasing the number of assays that can be performed by the same personnel compared with endpoint ELISA, while it maintains sensitivity and specificity.
Evaluation of Abbott CMV-M enzyme immunoassay for detection of cytomegalovirus immunoglobulin M antibody
Authors: Schaefer L , Cesario A , Demmler G , Plotkin S , Stagno S , Elrod C , Ringler J , Tustin N
Published: January 2020

The Abbott CMV-M enzyme immunoassay (EIA) for the qualitative determination of immunoglobulin M (IgM) antibody to cytomegalovirus in human serum was compared with the indirect fluorescent-antibody (IFA) test on 338 human serum specimens. Discordant specimens were evaluated by IFA following isolation of IgM fractions. Discordant specimens remaining after IFA testing were evaluated by an IgM-specific EIA (CYTOMEGELISA M; M.A. Bioproducts). After resolution of discordant specimens, the CMV-M EIA was 94.7% sensitive and 99.1% specific.