bluuebunny/crossref_metadata_2025 huggingface dataset:
Suicide phenomenon in mesophilic aeromonads as a basis for species identification
Authors: Namdari H , Bottone E J
Published: January 2020

The acetic acid-mediated suicide phenomenon in mesophilic aeromonads in conjunction with tests for aerogenicity and esculin hydrolysis served as the basis for species identification. Of 210 Aeromonas isolates tested at 30 degrees C, 88 were identified as Aeromonas hydrophila (nonsuicidal, aerogenic, esculin positive), 52 were identified as A. sobria (suicide variable, aerogenic, esculin negative), and 70 were identified as A. caviae (suicidal, anaerogenic, esculin positive). These identifications paralleled those achieved by biochemical criteria.
Comparison of isolates of Neisseria gonorrhoeae causing meningitis and report of gonococcal meningitis in a patient with C8 deficiency
Authors: Del Rio C , Stephens D S , Knapp J S , Rice R J , Schalla W O
Published: January 2020

We studied a previously healthy 20-year-old woman who presented with gonococcal meningitis. The gonococcal isolate, HT-1, was prototrophic by auxotyping, was protein I serovar IB-1, and agglutinated with wheat germ lectin. This isolate differed from the proline-requiring, serovar IA-1 and IB-4, wheat germ-agglutination-negative gonococcal isolates recovered from three patients during a recent outbreak of gonococcal meningitis in Philadelphia. HT-1 was killed by normal pooled human sera (greater than or equal to 98% at 30 min) but not effectively killed by the convalescent-phase sera of the patient (greater than 30% survival at 30 min). Similar results were obtained when mucosal and cerebrospinal fluid isolates from a Philadelphia patient were exposed to these sera, but mucosal and blood isolates from another Philadelphia case showed increased resistance to killing by normal pooled human sera. Further characterization revealed multiple differences in outer membrane and cellular proteins and lipopolysaccharide between case isolates. Absence of the L8 lipopolysaccharide epitope was noted for all isolates. Sera of our patient were found to have low total hemolytic complement (CH100 = 21 U/ml; normal = 55 to 100 U/ml) due to deficiency of C8 (C8 less than 1,000 CH50 U/ml; normal = greater than or equal to 16,000 CH50 U/ml). This is the first reported case of gonococcal meningitis occurring in a patient with a terminal-complement deficiency. Gonococcal meningitis is a rare complication of gonococcal bacteremia. Both defects in host defenses (e.g., terminal-complement deficiency) and organisms with unusual virulence appear to contribute to the pathogenesis of this complication of gonococcal bacteremia.
Use of a Chlamydia trachomatis DNA probe for detection of ocular chlamydiae
Authors: Dean D , Palmer L , Pant C R , Courtright P , Falkow S , O'Hanley P
Published: January 2020

We examined the efficacy of a Chlamydia trachomatis DNA probe in detecting ocular chlamydiae by comparing it with tissue culture isolation, direct fluorescent-antibody cytology, and clinical eye exams. In a trachoma-endemic area of Nepal, 430 Nepalese villagers were examined according to the World Health Organization trachoma grading scale. Upper tarsal conjunctival specimens from each subject were obtained for DNA probing, tissue culture, and fluorescent-antibody screening. Moderate to severe intensity of inflammation was found in 85 (21%) of 430 people studied. An additional 25 (7.2%) of 345 people with low or no intensity of inflammation also had microbiologically proven infection, which may reflect asymptomatic carriage. Compared with culture, the DNA probe had a sensitivity of 86.9% and a specificity of 91%. For direct fluorescent antibody versus culture, the values were 47.8 and 96.9%, respectively. Results from this study indicate that the DNA probe for C. trachomatis might be considered a valuable epidemiologic tool in screening trachoma-endemic populations for ocular chlamydiae.
Association of human immunodeficiency virus (HIV) p24 antigenemia with decrease in CD4+ lymphocytes and onset of acquired immunodeficiency syndrome during the early phase of HIV infection
Authors: Rinaldo C , Kingsley L , Neumann J , Reed D , Gupta P , Lyter D
Published: January 2020

Human immunodeficiency virus (HIV) p24 antigenemia was assessed in a longitudinal study of 52 homosexual men who developed serum antibody to HIV. Antibody seroconversion to HIV as defined by a positive HIV enzyme immunoassay (EIA) confirmed by Western (immuno-) blot was associated with three major patterns of HIV antigenemia. In the first pattern, a transient antigenemia was noted 6 (six subjects) and 12 (one subject) months prior to detection of antibody by HIV EIA and Western blot in 7 (13.5%) of the 52 men. Use of an EIA employing a recombinant envelope protein (ENV9) was able to detect antibody in four of these seven men at the time of this early antigenemia. In the second pattern, HIV p24 antigenemia occurred in 8 (15.4%) of the 52 subjects within the first 12 months after HIV antibody seroconversion. No p24 antigen was detected in the 37 (71.1%) remaining subjects. CD4+ cell numbers were lower in antigen-positive men before and after antibody seroconversion. Development of acquired immunodeficiency syndrome (AIDS) or AIDS-related complex was strongly associated with evidence of persistent p24 antigenemia during the early, postseroconversion period. HIV p24 antigenemia may be of value in determining appropriate cohorts for drug therapy trials for subjects with early-phase HIV infection.
Single-step, chromogenic Limulus amebocyte lysate assay for endotoxin
Authors: Lindsay G K , Roslansky P F , Novitsky T J
Published: January 2020

A new reagent for the chromogenic Limulus amebocyte lysate (LAL) assay is described. LAL was formulated for optimal performance in either an endpoint procedure or a kinetic procedure with the chromogenic substrate, buffer, and LAL components colyophilized as a single reagent. The kinetic chromogenic method required an incubating microplate reader coupled to a computer for collection and analysis of data. The kinetic method had a longer incubation time than the endpoint method and spanned a range of over 3 orders of magnitude compared with the 1-order-of-magnitude range of the endpoint assay. The kinetic method was less subject to operator error, since readings were continuous and automatic. The endpoint test was more operator intensive, requiring both addition of acetic acid to stop the reaction and transfer of the sample to the reading device. A single-step chromogenic reagent was also prepared without lyophilization by mixing reconstituted gel clot LAL with a buffer and a chromogenic substrate. The reagent prepared in this manner performed as well as the colyophilized agent.
Comparison of two rapid microscopic methods and culture for detection of Chlamydia trachomatis in ocular and nasopharyngeal specimens from infants
Authors: Roblin P M , Hammerschlag M R , Cummings C , Williams T H , Worku M
Published: January 2020

The data available for the diagnosis of chlamydial infections in infants which compare direct fluorescent-monoclonal-antibody stains (DFAs) with culture are limited to one reagent, MicroTrak (Syva Inc., Palo Alto, Calif.). We therefore performed a comparison of Pathfinder (Kallestad Diagnostics, Chaska, Minn.) and MicroTrak with chlamydia culture. Paired conjunctival and nasopharyngeal specimens for DFAs and cultures were obtained from 56 infants less than 1 month of age with conjunctivitis. The sensitivities for detecting C. trachomatis in conjunctival specimens with MicroTrak and Pathfinder were 93.8 and 88.2%, respectively, and the specificities were 87.5 and 94.9%, respectively. The DFA tests on nasopharyngeal specimens from infants with conjunctivitis did not perform as well. The sensitivities for Pathfinder and MicroTrak were 33 and 50%, respectively. There were a total of six patients with culture-positive chlamydial conjunctivitis whose nasopharyngeal specimens were DFA positive and culture negative; four of the specimens were positive by both DFAs. These six discordant specimens were further evaluated by preparing pellets and smears of the original culture specimens. All six contained typical fluorescing elementary bodies when stained with the Syva DFA reagent.
Use of monoclonal antibodies to type Shigella flexneri in Bangladesh
Authors: Carlin N I , Rahman M , Sack D A , Zaman A , Kay B , Lindberg A A
Published: January 2020

A panel of 10 mouse and rat monoclonal antibodies specific for different type- and group-specific O-antigenic determinants of Shigella flexneri lipopolysaccharide was used to serotype 240 isolates of S. flexneri from Bangladesh. Three immunoglobulin M antibodies were used in a direct slide agglutination test; seven immunoglobulin G antibodies were absorbed to Staphylococcus aureus and used in a coagglutination assay. All but 13 of the isolates could be serotyped by using the monclonal antibodies. The six most common serotypes were (in descending order) 2a, 2b, Y (E1037), 1a, 3a, and 1b and accounted for more than 80% of all isolates. Two of the nontypable strains were found to be of a new provisional serotype of S. flexneri (T. Wehler and N.I.A. Carlin, Eur. J. Biochem. 176:471-476, 1988). The 11 remaining strains were found to be rough and therefore nontypable. The serotyping scheme based on the panel of monoclonal antibodies is specific and holds the potential to be developed into a useful tool for epidemiological investigation. The study also demonstrates that the recently described E1037 antigen is commonly found among at least four serotypes (4a, 6, X, and Y) of S. flexneri.
Evaluation of the Titertek-NF system for identification of gram-negative nonfermentative and oxidase-positive fermentative bacteria
Authors: Kämpfer P , Dott W
Published: January 2020

The Titertek-NF (TT-NF) system (Flow Laboratories GmbH, Meckenheim, Federal Republic of Germany) was evaluated for the identification of 1,289 strains of gram-negative, nonfermentative bacteria and some gram-negative, oxidase-positive bacteria. The oxidase test was also performed. Identifications were classified as correct, not identified (two or more taxa possible and identification score of less than 80%; supplementary tests for furthering the identification were not performed), and incorrect. Correct identification results were further subdivided by the correct level of species or biotype identification as greater than or equal to 98% (category a), 90 to 97% (category b), and 80 to 89% (category c). When compared with conventional identification results, the TT-NF system correctly identified 90.3% of strains (1,164 of 1,289 strains), with 72.5% (935 strains) belonging to category a, 14.7% of strains (189 strains) belonging to category b, and 3.1% of strains (40 strains) belonging to category c. Among the remaining strains, 104 (8.1%) were not identified and 14 (1.1%) were misidentified, and the system failed to generate identification results for 7 strains (0.5%). Reactions within the TT-NF system were reproducible, with an estimated probability of erroneous test results of 0.2%.
Species-specific detection of Legionella pneumophila in water by DNA amplification and hybridization
Authors: Starnbach M N , Falkow S , Tompkins L S
Published: January 2020

A sensitive detection system specific for Legionella pneumophila in water was developed. This system is based on amplification of a chromosomal DNA sequence from L. pneumophila by the polymerase chain reaction, followed by detection of the amplified product by hybridization of a radiolabeled oligodeoxynucleotide. After 35 cycles of amplification, a water sample which had been seeded with 35 CFU of L. pneumophila contained sufficient amplified DNA to be detected on dot blots. Bacteria of other genera tested did not generate positive signals under these conditions. Application of this technique to environmental water samples may help identify the natural reservoirs of nosocomial and community-acquired L. pneumophila infections.
Development and evaluation of enzyme-linked immunosorbent assays for detection of shiga-like toxin I and shiga-like toxin II
Authors: Downes F P , Green J H , Greene K , Strockbine N , Wells J G , Wachsmuth I K
Published: January 2020

Shiga-like toxin (SLT)-producing Escherichia coli has been associated with a spectrum of human illnesses, including hemorrhagic colitis and hemolytic uremic syndrome. It produces at least two antigenically distinct toxins designated SLT-I and SLT-II, which have been implicated in disease. Currently available toxin assays, however, are not suitable for most clinical or public health laboratories. In this study, we have developed two sandwich enzyme-linked immunosorbent assays (ELISAs) based on toxin-specific murine monoclonal capture antibodies and rabbit polyclonal second antibodies which are specific for SLT-I and SLT-II. The SLT-I ELISA detected 200 pg of purified SLT-I, and the SLT-II ELISA detected 75 pg of purified SLT-II. The types of SLT produced by 166 human and 54 animal isolates of E. coli that produced moderate to high levels of toxin were determined by the ELISA, and results were confirmed by cytotoxin neutralization assays. With the exception of results from three strains, the tests agreed on the types of toxin present. DNA probe assays of 86 of 87 isolates also agreed with the ELISA and neutralization results. Although the SLT-II ELISA was specific for the SLT-II variant produced by porcine edema strains, most of the isolates examined produced levels of toxin (less than 50 50% cytotoxic doses [CD50] per ml) below the detection limit of the test. The ELISAs were not sufficiently sensitive to consistently detect low levels of toxin (less than 50 CD50 per ml) found in fecal extracts. On the basis of these findings, both ELISAs appeared to detect significant levels of SLT-I ( > 100 CD50 per ml) and SLT-II ( > 50 CD50 per ml) in E. coli culture extracts and should be useful diagnostic tools in many microbiology laboratories.
Chlamydia trachomatis and parainfluenza 2 virus: a shared antigenic determinant?
Authors: Fox A S , Saxon E M , Doveikis S , Beem M O
Published: January 2020

A tracheal aspirate from which parainfluenza 2 (PI-2) virus but not chlamydiae was isolated demonstrated positive immunofluorescence of elementary body- and reticulate body-like particles on direct examination with anti-chlamydia monoclonal antibodies (Syva Co.). In subsequent studies, we found this reagent to show specific staining of this strain of PI-2 as well as of 3 of 18 additional PI-2 strains that were evaluated.
Laboratory characterization of a swine influenza virus isolated from a fatal case of human influenza
Authors: Rota P A , Rocha E P , Harmon M W , Hinshaw V S , Sheerar M G , Kawaoka Y , Cox N J , Smith T F
Published: January 2020

A swine influenza virus-like type A (H1N1) virus, designated A/Wisconsin/3523/88, was isolated in September 1988 from a Wisconsin woman who had died with primary viral pneumonia. Antigenic analyses with hemagglutinin-specific monoclonal antibodies and postinfection ferret serum indicated that the hemagglutinin of A/Wisconsin/3523/88 was antigenically closely related to viruses currently circulating in swine. Genetic analysis of the A/Wisconsin/3523/88 virus by RNA fingerprinting and partial RNA sequence analysis of seven of the eight segments indicated that the genome of the human isolate was similar to that of enzootic swine viruses. These laboratory data supported the epidemiologic findings that this human infection occurred by transmission of an enzootic swine influenza virus and that the virus showed no major genetic changes potentially related to increased pathogenesis.
Comparison of conventional staining methods and monoclonal antibody-based methods for Cryptosporidium oocyst detection
Authors: Arrowood M J , Sterling C R
Published: January 2020

The sensitivity and specificity of seven microscopy-based Cryptosporidium oocyst detection methods were compared after application to unconcentrated fecal smears. The seven methods were as follows: (i) a commercial acid-fast (AF) stain (VOLU-SOL) method, (ii) Truant auramine-rhodamine (AR) stain method, (iii) fluorescein-conjugated C1B3 monoclonal antibody (MAb) direct fluorescence method, (iv) OW3 MAb indirect fluorescence method, (v) biotinylated OW3 indirect fluorescence method, (vi) biotinylated OW3-indirect diaminobenzidine (DAB) method, and (vii) biotinylated OW3-aminoethylcarbazole (AEC) method. A total of 281 randomly collected Formalin-fixed fecal samples (submitted to the Maricopa County Health Department, Phoenix, Ariz.) and 30 known positives (Formalin-fixed and K2Cr2O7-preserved stools from our laboratory) were examined in a blind test; 32 of 311 samples (10.3%) were confirmed positive. Of the confirmed positives, 40.6% were identified by the AF method, 93.8% were identified by the AR method, 93.8% were identified by the C1B3 method, 81.3% were identified by the OW3-DAB method, 71.9% were identified by the OW3-AEC method, 100% were identified by the OW3 indirect fluorescence method, and 100% were identified by the biotinylated OW3 indirect fluorescence method. False-positives were encountered by the AF and AR methods (52.0 and 85.7% specificity, respectively), while no false-positives encountered by the MAb-based methods. Oocysts in infected tissue sections were easily detected by the MAb-based methods.
Comparison of in situ hybridization and monoclonal antibodies for early detection of cytomegalovirus in cell culture
Authors: McClintock J T , Thaker S R , Mosher M , Jones D , Forman M , Charache P , Wright K , Keiser J , Taub F E
Published: January 2020

The abilities of each of four diagnostic tests--direct fluorescent monoclonal antibody (direct FA) staining, indirect fluorescent monoclonal antibody (indirect FA) staining, in situ hybridization with biotinylated DNA probes, and in situ hybridization with DNA probes directly linked to enzymatically active horseradish peroxidase-to detect cytomegalovirus soon after culture were compared. Only the indirect FA test and the in situ hybridization method with directly linked HRP-DNA probes provided consistent and reliable cytomegalovirus detection as early as 15 h postinfection.
Is ingestion of milk-associated bacteria by premature infants fed raw human milk controlled by routine bacteriologic screening?
Authors: Law B J , Urias B A , Lertzman J , Robson D , Romance L
Published: January 2020

Expressed human milk is often used to feed premature infants. Raw milk contains bacteria which may be a source of infection. Milk banks have developed screening programs which combine periodic quantitative milk cultures with arbitrary rules specifying limits of bacterial concentration. It is unknown whether such programs succeed in preventing infants from being fed milk containing bacteria. At the Health Sciences Centre (Winnipeg, Manitoba, Canada), milk is screened once weekly. When a woman's milk is found to have excess bacteria, it is discarded only if she is an unrelated donor (as opposed to an infant's mother). To assess the effectiveness of this screening program, we determined the frequency at which infants fed raw human milk were exposed to milk-associated bacteria and compared the bacterial contents of donor and maternal milk. From February 1986 to April 1987, all human milk fed to 98 premature infants during the first 2 weeks of feeding (n = 10,128 feeds) was cultured quantitatively. Among study infants, 100% were exposed at least once to coagulase-negative staphylococci, 41% were exposed to Staphylococcus aureus, and 64% were exposed to gram-negative bacilli. The proportions of feeds containing bacteria and the quantities (log10 CFU [mean +/- standard deviation]) ingested per positive feed were: 39% and 5.9 +/- 0.5 for coagulase-negative staphylococci; 2.4% and 5.1 +/- 1.0 for S. aureus; and 5.2% and 4.8 +/- 1.1 for gram-negative bacilli. There were no adverse events attributable to ingestion of milk-associated bacteria. Milk coagulase-negative staphylococcal isolates were multiply antibiotic susceptible, whereas infant isolates were antibiotic resistant. Donor milk was significantly less likely than maternal milk to contain coagulase-negative staphylococcal species in any quantity (40 versus 93% of samples, respectively [P < 0.001]) or in concentrations exceeding 10(8) CFU/liter (3 versus 27% of samples, respectively [P < 0.0001]). There was no difference between milk from either source in terms of S. aureus or gram-negative bacterial content (4 to 6%). These results suggest that the Health Sciences Centre screening program is effective in limiting the number of harmless coagulase-negative staphylococcal species but has no impact on the quantity of potentially pathogenic bacteria ingested by premature infants. Implications for screening donor milk are discussed.
Characterization by enzyme-linked immunosorbent assay using subgroup- and serotype-specific monoclonal antibodies of human rotavirus obtained from diarrheic patients in Bangladesh
Authors: Ahmed M U , Taniguchi K , Kobayashi N , Urasawa T , Wakasugi F , Islam M , Shaikh H , Urasawa S
Published: January 2020

By enzyme-linked immunosorbent assay with group A-, subgroup-, and serotype-specific monoclonal antibodies (MAbs), we tested 414 stool specimens collected from pediatric and adult patients hospitalized with acute gastroenteritis between January and June 1988. Of 414 specimens tested, 124 (30%) were positive for group A rotavirus. The subgroup was determined in 110 specimens (88.7%); 16.1% were subgroup I, and 72.6% were subgroup II. Two specimens reacted with both subgroup I- and subgroup II-specific MAbs. Serotype determinations showed that serotype 1 (38.4%) was predominant over serotypes 2 (28.2%), 3 (2.5%), and 4 (23%). Three specimens reacted with more than one serotype-specific MAb. While the frequency of serotype 1 was highest in the two hospitals in Mymensingh, serotype 2 was most prevalent in one hospital in Dhaka. All human rotavirus strains with subgroup I and serotype 2 specificities showed a short electropherotype, and all but one strain with subgroup II and serotype 1, 3, or 4 specificities exhibited a long electropherotype.
Direct detection of Neisseria gonorrhoeae with monoclonal antibodies characterized by serotyping reagents
Authors: Rajasekariah G R , Edward S , Shapira D , Tapsall J , Walsh J , Ho J , Hopper K , Pucci A
Published: January 2020

A panel of monoclonal antibodies (MAbs) directed to outer membrane protein I were generated with the ultimate aim of detecting Neisseria gonorrhoeae in patient samples by a direct immunofluorescence (IF) test. In an initial evaluation of the sensitivity of these reagents, a cocktail of six IF MAbs recognized 491 (91%) of 540 gonococci isolates from several centers in Sydney, Australia. IF MAbs designated 185 and 228 recognized serovars of WI serogroup and IF MAbs 208, 210, and 312 recognized serovars of WII/III serogroup. IF MAb 198 recognized serovars within both serogroups. Three additional IF MAbs, designated 322, 323, and 330, were then generated by using strains which failed to react with the original MAb cocktail and which belonged to particular serovars. The new cocktail of nine IF MAbs recognized 96% of the gonococcal isolates, which incidentally contained representatives of serovars shown to have a worldwide distribution in previous studies. Although subtle differences were apparent in the reaction patterns found with coagglutination (serotyping) and IF, there nonetheless seems to be merit in the approach of continually evaluating the sensitivity of diagnostic reagents such as MAbs. This is especially true with an organism such as N. gonorrhoeae, which has the capacity to regularly alter the antigenic structure of its outer membrane proteins.
Immunoaffinity isolation and partial characterization of the Coccidioides immitis antigen detected by the tube precipitin and immunodiffusion-tube precipitin tests
Authors: Zimmer B L , Pappagianis D
Published: January 2020

The antigen participating in the tube precipitin (TP) serologic test for coccidioidomycosis was isolated from mycelial-phase antigen (coccidioidin) by immunoaffinity and characterized by various analytical procedures. This was accomplished by first preparing the antigen-antibody precipitate by using antigen and human serum positive for TP (immunoglobulin M) antibody and then liberating the antigen by digestion with pronase. This protease destroyed the antibody and left the antigen intact as indicated by immunodiffusion-TP. The coccidioidal antigen was isolated from the proteolytic digest by using size exclusion chromatography. DEAE chromatography of this antigen yielded two fractions with immunodiffusion-TP reactivity which had average molecular sizes of 225 and 140 kilodaltons, respectively. The presence of carbohydrate and amino acids indicated that the antigen(s) is a glycopeptide. Compositional analysis showed that one fraction contained 3-O-methylmannose, mannose, and glucose in a ratio of 8:1.2:1, whereas the second fraction contained 3-O-methylmannose, mannose, glucose, and galactose in a ratio of 1:1:1:1. The amino acids glycine, alanine, serine, threonine, aspartic acid plus asparagine, and glutamic acid plus glutamine constituted 60 to 70% of the amino acids in both glycopeptides. Neither antigen could be detected entering the gel in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Lectin affinity provided evidence of a high-mannose asparagine-linked glycopeptide in the first peak and an asparagine-linked glycopeptide with a biantennary complex-type structure in the second peak.
Immunofluorescence assay for human immunodeficiency virus antibody: investigation of cell fixation for virus inactivation and antigen preservation
Authors: Fauvel M , Ozanne G
Published: January 2020

Four cell fixation procedures were investigated for their abilities to inactivate human immunodeficiency virus (HIV) and preserve its antigenicity for antibody detection by immunofluorescence in MOLT-4-T4 cells. Air-dried cell smears were fixed in cold acetone, in acetone-methanol (1:1), in acetone-methanol (1:1) followed by 70% ethanol and then methanol, or in paraformaldehyde-acetone. Acetone alone did not inactivate cell-associated HIV, but the other three procedures did. HIV inactivation was achieved by storage of acetone-fixed cells at -70 degrees for 40 days. Antigenicity was measured by immunofluorescence assay titrations of selected human sera, a cerebrospinal fluid, and a gp41 monoclonal antibody. Acetone provided the best fixation as measured by fluorescence intensity and antibody titers. The other fixation methods all yielded weaker fluorescence signals and/or decreased titers. Acetone fixation and storage for 40 days at -70 degrees C provides safe and accurate immunofluorescence assay reagents.
Serodiagnosis of scrub typhus with antigens immobilized on nitrocellulose sheet
Authors: Urakami H , Yamamoto S , Tsuruhara T , Ohashi N , Tamura A
Published: January 2020

This study was designed to develop a simple method for serodiagnosis of scrub typhus. The basis of the method is detection of anti-Rickettsia tsutsugamushi antibody in patient serum by reaction with antigens dot blotted on a nitrocellulose sheet (NCS). The final evaluation of the reaction is performed by observing the color intensity which develops as a result of sequential treatments of the NCS with peroxidase-conjugated anti-human immunoglobulin G or immunoglobulin M antibody and with the substrate of the enzyme. After various trials, we found that the best results were obtained by using a purified antigen which adhered to an NCS at 0.2 to 2 micrograms of protein per dot and a test serum diluted 1,000- to 4,000-fold. Under these conditions, almost all antibody-positive sera showed a distinct color at the dot on the NCS, so that a positive reaction could be distinguished by the naked eye from a negative reaction with antibody-negative sera, which developed only a faint color. A comparison of the results of screening of antibody-positive and -negative sera by this method and the immunofluorescence test showed that both methods produced similar results. From these results, it is concluded that this dot immunoassay can be useful for the serodiagnosis of scrub typhus.
Performance of serological assays for early detection of human immunodeficiency virus type 1 seroconversion
Authors: Farzadegan H , Taylor E , Hardy W , Odaka N , Polk B F
Published: January 2020

Early detection of sexually transmitted human immunodeficiency virus type 1 (HIV-1) infection was investigated in newly infected persons to determine the sensitivities of currently available serologic techniques. Serial serum samples were obtained from 51 newly infected persons in a cohort of 1,153 homosexual or bisexual men participating in the Baltimore Center of the Multi-Center AIDS Cohort Study during the first 2.5 years of follow-up. Of 51 participants, 45 seroconverted between any two seminannual visits and 6 were found to have been infected just prior to study entry. Five enzyme-linked immunosorbent assays (ELISAs), two immunoblots, and an HIV-1 P24 antigen capture assay were performed on a panel of all serial serum samples from these individuals. The sensitivity of ELISAs varied between 50 and 84% in seroconverters with less-developed antibody response. In this group of seroconverters, the most sensitive antibody assay was an immunoblot from Biotech (95%) and HIV-1 P24 was found infrequently (9.5%). The sensitivities of ELISAs and immunoblot were 100% in individuals with more-developed antibody patterns, and no HIV-1 P24 was detected among them.
Fluorescent-antibody-negative penicillinase-producing Neisseria gonorrhoeae
Authors: Walton D T
Published: January 2020

The incidence of monoclonal-fluorescent-antibody-negative penicillinase-producing Neisseria gonorrhoeae is not known. Two isolates which could not be identified by using a commercial monoclonal fluorescent-antibody conjugate are described. The use of more than one confirmatory method is recommended.
Evolution of the levels of soluble interleukin-2 receptors during Plasmodium falciparum and P. vivax malaria
Authors: Deloron P , Lepers J P , Coulanges P
Published: January 2020

Increased levels of soluble interleukin-2 receptors (IL-2R) in serum were observed in both Plasmodium falciparum- and P. vivax-infected individuals compared with nonparasitemic subjects. Clinical symptoms of P. falciparum malaria were associated with higher levels of soluble IL-2R. Temporal evolution in serum of IL-2R during the course of a malaria attack mimicked the kinetics of soluble IL-2R under experimental conditions.
Sensitivity and specificity of pooled versus individual sera in a human immunodeficiency virus antibody prevalence study
Authors: Cahoon-Young B , Chandler A , Livermore T , Gaudino J , Benjamin R
Published: January 2020

We evaluated the efficacy of testing pooled versus individual sera for the detection of human immunodeficiency virus antibody. A total of 5,000 individual specimens and 500 pools of 10 specimens each were assayed by an enzyme-linked immunosorbent assay. There was complete agreement in human immunodeficiency virus enzyme-linked immunosorbent assay reactivity for pooled versus individual specimens. An estimated savings of 60 to 80% (labor and supplies) can be realized dependent upon pooling and assay format.
Determination by enzyme-linked immunosorbent assay of immunoglobulin G (IgG), IgM, and IgA to Brucella melitensis major outer membrane proteins and whole-cell heat-killed antigens in sera of patients with brucellosis
Authors: Araj G F , Kaufmann A F
Published: January 2020

An enzyme-linked immunosorbent assay was used to compare Brucella melitensis major outer membrane proteins (MOMP) and whole-cell heat-killed antigens (HK) in measuring antibrucella immunoglobulin G (IgG), IgM, and IgA in sera of brucellosis patients and controls. Antibodies to MOMP were generally similar to those against HK, and the correlation coefficients between the two antigens and IgG, IgM, and IgA in patients varied between 0.73 and 0.94. Both antigens are comparably suitable in detecting antibrucella immunoglobulin isotypes for the serologic diagnosis of patients with brucellosis, with high (greater than or equal to 95%) sensitivity and specificity.
Use of a group-reactive and other monoclonal antibodies in an enzyme immunodot assay for identification and presumptive serotyping of aquatic birnaviruses
Authors: Caswell-Reno P , Lipipun V , Reno P W , Nicholson B L
Published: January 2020

A panel of monoclonal antibodies (MAbs) was prepared and used to develop an enzyme immunodot assay for the rapid identification and presumptive serotyping of aquatic birnaviruses. Comparison of the reaction patterns of these MAbs with representative virus isolates indicated that one MAb recognizes a serogroup-reactive epitope and can therefore be used for identification of all serogroup A aquatic birnaviruses, the predominant serotype worldwide. Other MAbs exhibited more restrictive specificities, permitting the presumptive serotyping of viruses of the three recognized serotypes and the identification of some individual strains. This assay, in which MAbs are used, is more efficient in terms of time, cost, and case of performance and provides significant advantages in specificity and standardization compared with currently used tests.
Rapid and sensitive method for the detection of serum hepatitis B virus DNA using the polymerase chain reaction technique
Authors: Kaneko S , Feinstone S M , Miller R H
Published: January 2020

We have developed a rapid procedure for the detection of serum hepatitis B virus (HBV) DNA using the polymerase chain reaction (PCR) technique. HBV DNA is released from virions by incubating serum with 0.1 M NaOH for 60 min at 37 degrees C. The mixture is brought to neutral pH with HCl, and the HBV DNA sequences are detected by agarose gel electrophoresis and ethidium bromide staining after PCR amplification with two successive sets of primer pairs. The detection limit of this method (i.e., 10(-5) pg of HBV DNA) is equivalent to that previously determined by one round of PCR amplification and Southern blot hybridization analysis. The advantages are that the assay can be completed in 1 day, is very sensitive, and does not require the use of radiolabeled reagents.
Production of a toxic shock syndrome toxin variant by Staphylococcus aureus strains associated with sheep, goats, and cows
Authors: Ho G , Campbell W H , Bergdoll M S , Carlson E
Published: January 2020

A toxic shock syndrome toxin (TSST) variant with an isoelectric point (pI) of 8.6 produced by an ovine-associated Staphylococcus aureus strain was described previously. Analysis of additional strains associated with sheep, goats, cows, and humans by isoelectric focusing with immunoblotting using monoclonal antibodies revealed that all 18 strains associated with sheep and all 12 strains associated with goats produced the TSST variant. Only 1 of 10 bovine-associated strains and no human-associated strains produced the variant, whereas the others produced TSST-1 (pI between 7.0 and 7.2). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis with immunoblotting indicated that both TSST-1 and the TSST variant had a molecular size of 24 kilodaltons.
Indirect enzyme-linked immunosorbent assay for zygomycosis
Authors: Kaufman L , Turner L F , McLaughlin D W
Published: January 2020

A 2-h indirect enzyme-linked immunosorbent assay (ELISA) using homogenate antigens of Rhizopus arrhizus and Rhizomucor pusillus was developed and compared with the existing immunodiffusion (ID) test for zygomycosis, using homogenate antigens of R. arrhizus. Utilizing 1:400 as a minimally positive ELISA titer, 33 of 43 proven cases of zygomycosis were diagnosed. The sensitivity of the ELISA was 81%. The ID test, in contrast, detected only 21 cases and demonstrated a sensitivity of 66%. The specificity of the ELISA was 94%, whereas that of the ID test was 91%. Nonspecific ELISA reactivity was particularly evident with sera from patients with aspergillosis and candidiasis. With the antigens now available, the ELISA was unable to generically or specifically identify the etiologic agents.
Isolation and characterization of catalase-negative and catalase-weak strains of Campylobacter species, including "Campylobacter upsaliensis," from humans with gastroenteritis
Authors: Taylor D E , Hiratsuka K , Mueller L
Published: January 2020

During 1987 and 1988, nine strains of catalase-negative or -weak Campylobacter species were isolated in Alberta, Canada. DNA hybridization studies demonstrated that seven strains were "Campylobacter upsaliensis," one strain was highly homologous with Campylobacter jejuni DNA, and one strain was a campylobacter unrelated to the other two species. All "C. upsaliensis" strains were hippurate negative, and six of seven were susceptible to cephalothin. The unusual variant of C. jejuni was hippurate positive and cephalothin resistant, whereas the unclassified strain was hippurate negative and resistant to intermediate levels of cephalothin. All patients from whom "C. upsaliensis" was isolated had diarrhea. Five of the patients were children two years old or younger, and two were adults. In this study, all catalase-negative and -weak strains were isolated from stool specimens by using a charcoal-based selective medium containing 32 micrograms of cefaperazone per ml and which was described by Hutchinson and Bolton (D. N. Hutchinson and F. J. Bolton, J. Clin. Pathol. 37:956-957, 1984).
Effect of age of shell vial monolayers on detection of cytomegalovirus from urine specimens
Authors: Fedorko D P , Ilstrup D M , Smith T F
Published: January 2020

The effect of age of MRC-5 cell monolayers in shell vials on the detection of cytomegalovirus (CMV) from urine was evaluated. When the AD169 strain of CMV was used, 8-day-old monolayers had a higher mean count of fluorescent foci than 15-day-old monolayers did (5.78 versus 2.86) (P less than 0.02) and were more frequently positive (21 of 23 shell vials versus 14 of 22 shell vials) (P less than 0.04). Commercial shell vials used for clinical specimens were evaluated in groups of 8- to 11-, 12- to 15-, and 8- to 15-day-old monolayers. When compared with laboratory-prepared shell vials ranging in age from 3 to 9 days, commercial shell vials had a lower number of fluorescent foci in all groups (P less than 0.03, P less than 0.0001, and P less than 0.0001, respectively), the 12- to 15- and 8- to 15-day-old groups were less frequently positive (P less than or equal to 0.02 and P less than 0.02, respectively), and all three groups were more susceptible to the toxic effects of urine (P less than 0.0001, P less than 0.01, and P less than 0.0001, respectively). For all 191 specimens cultured (8- to 15-day-old group), one or both monolayers were destroyed in 60 (31.4%) specimens compared with 9 (4.7%) specimens toxic to laboratory-prepared shell vials (P less than 0.0001). Both the decreased sensitivity of older MRC-5 cells and the increased sensitivity to the toxic effects of urine made commercial shell vial less sensitive than laboratory-prepared shell vials for the detection of CMV.
Rapid method for the detection of DNase of campylobacters
Authors: Hänninen M L
Published: January 2020

A rapid agar diffusion method for the detection of DNase production of Campylobacter jejuni, C. coli, and C. pylori was developed. A strong pink zone indicating DNA hydrolysis was seen around the wells after 20 to 24 h of aerobic incubation at 37 degrees C. Pretreatment of cells with polymyxin B, which releases the cell-associated DNase, both shortened the time needed to read positive results to 8 h and increased the zone size.
Development and epidemiological applications of a bacteriophage typing system for typing Pasteurella multocida
Authors: Nielsen J P , Rosdahl V T
Published: January 2020

A bacteriophage typing system was developed for typing toxigenic and nontoxigenic strains of Pasteurella multocida. A phage set of 24 phages with different lytic spectra was isolated after mitomycin treatment of P. multocida strains, isolated mainly from pigs from herds with atrophic rhinitis. On a test set of 97 different strains isolated from pigs, these 24 phages were able to type 87% of the strains. The 97 test strains could be subdivided into 31 different types by reaction with the 24 phages. The reproducibility after subculture and storage of the strains was good (95%). Phage typing of 217 toxigenic P. multocida field isolates from 37 pig herds predominately with clinically atrophic rhinitis resulted in 18 different phage types and an overall typability of 68%. Of 24 herds from which more than three isolates of toxigenic P. multocida were obtained, a single phage type was demonstrated in 5 herds, while in 9 herds a single phage type represented at least half of the isolates. The phage types in the remaining 10 herds revealed no dominating phage type. The phage typing system described appears to be a valuable epidemiological tool for studying the spread of P. multocida.
Epidemiology and pathogenicity of Blastocystis hominis
Authors: Doyle P W , Helgason M M , Mathias R G , Proctor E M
Published: January 2020

A prospective study was performed on a large outpatient population to evaluate the epidemiology and pathogenicity of Blastocystis hominis. Patients with stool specimens positive for B. hominis and negative for other bacterial and parasitic pathogens were sent a questionnaire and were requested to submit a follow-up specimen for ova-and-parasite examination. B. hominis was identified in 530 of 16,545 specimens (3.2%). There was a spectrum of clinical-pathological presentations in the 143 patients evaluated. An asymptomatic carrier state was seen in 19 patients. Fifteen patients had an illness consistent with acute self-limited B. hominis gastroenteritis, and 21 patients had chronic gastroenteritis associated with B. hominis. In the epidemiological evaluation of 130 patients, the most common symptoms were watery diarrhea, abdominal pain, and gas. We did not find a statistically significant association between the number of organisms present and the disease state. In summary, our results are consistent with a role for B. hominis in acute and chronic gastroenteritis; however, further detailed studies are necessary to determine whether that role is one of association or causation.
Evaluation of isolator system and large-volume centrifugation method for culturing body fluids
Authors: Elston H R , Wang M , Philip A
Published: January 2020

The Isolator system was compared with the large-volume centrifugation method for processing and recovering organisms from body fluids other than blood, cerebrospinal fluid, and urine. A total of 155 body fluid samples were processed for the recovery of clinically significant organisms. Of the 55 positive cultures, Isolator detected 94% and the large-volume centrifugation method detected 64%. The time necessary to indicate positivity was not significantly different in the two methods; however, in five cases, the Isolator system yielded clinically significant organisms 24 h sooner than the conventional method. The Isolator system was found to be a more sensitive alternative than the conventional large-volume centrifugation method.
Correlation between esterase electrophoretic types and capsular polysaccharide types 5 and 8 among methicillin-susceptible and methicillin-resistant strains of Staphylococcus aureus
Authors: Branger C , Goullet P , Boutonnier A , Fournier J M
Published: January 2020

The relationship between capsular polysaccharide types 5 and 8 and esterase electrophoretic types (zymotypes) in 160 French clinical isolates of Staphylococcus aureus was studied. Methicillin-susceptible strains of capsular types 5 and 8 were represented by 11 zymotypes, indicating a high polymorphism. Methicillin-resistant strains were mainly distributed in only two distinct populations. The predominant population was represented by strains of zymotype 6 and capsular type 5, and the second population was represented by strains of zymotype 14 and capsular type 8.
Human immunodeficiency virus type 1 detected in all seropositive symptomatic and asymptomatic individuals
Authors: Jackson J B , Kwok S Y , Sninsky J J , Hopsicker J S , Sannerud K J , Rhame F S , Henry K , Simpson M , Balfour H H
Published: January 2020

Between February 1987 and October 1988, peripheral mononuclear blood cells (PBMC) from 409 adult individuals antibody positive by Western (immuno-)blot for human immunodeficiency virus type 1 (HIV-1) (56 acquired immunodeficiency syndrome [AIDS] patients, 88 patients with AIDS-related complex, and 265 asymptomatic individuals) were consecutively cultured for HIV-1 or tested for the presence of HIV-1 DNA sequences by a polymerase chain reaction assay (PCR). We isolated HIV-1 or detected HIV-1 DNA sequences from the PBMC of all 409 HIV-1 antibody-positive individuals. None of 131 healthy HIV-1 antibody-negative individuals were HIV-1 culture positive, nor were HIV-1 DNA sequences detected by PCR in the blood specimens of 43 seronegative individuals. In addition, HIV-1 PCR and HIV-1 culture were compared in testing the PBMC of 59 HIV-1 antibody-positive and 20 HIV-1 antibody-negative hemophiliacs. Both methods were found to have sensitivities and specificities of at least 97 and 100%, respectively. In contrast, the sensitivities of serum HIV-1 antigen testing in AIDS patients and asymptomatic seropositive patients were 42 and 17%, respectively. Our ability to directly demonstrate HIV-1 infection in all HIV-1 antibody-positive individuals provides definitive support that HIV-1 antibody positivity is associated with present HIV-1 infection. Moreover, the sensitivities and specificities of PCR and culture for the detection of HIV-1 appear to be equivalent, and both methods are superior to testing for HIV-1 antigen in serum for the direct detection of HIV-1.
Application of monoclonal antibodies to the detection of black-pigmented Bacteroides spp. in subgingival plaques by immunoslot blot assay
Authors: Hanazawa S , Tanaka S , Kin M , Amano S , Nakada K , Masuda T , Kitano S
Published: January 2020

The aim of the present study was to assess the application of monoclonal antibodies to the detection of black-pigmented Bacteroides spp. in subgingival plaques by immunoslot blot assay. Subgingival plaque samples from adult periodontal patients were examined by immunoslot blot assay with monoclonal antibodies that specifically recognize Bacteroides gingivalis, Bacteroides intermedius serogroups I and II, and Bacteroides melaninogenicus. The assay can detect specifically these Bacteroides spp. in the subgingival plaques. Therefore, we investigated the distribution of these Bacteroides spp. in the subgingival plaques of patients classified by Russell's periodontal index. Reactivities of their plaques with monoclonal antibodies toward B. gingivalis and B. intermedius serogroup I were clearly related to the severity of the periodontal disease, but this was not the case with B. intermedius serogroup II and B. melaninogenicus. These results indicate that this immunoslot blot assay using monoclonal antibodies toward these Bacteroides spp. provides simple detection and monitoring of these organisms in periodontal patients.