bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of enzyme-linked immunosorbent assay and hemagglutination inhibition in a seroepidemiological study of influenza type C infection
Authors: Troisi C L , Monto A S
Published: January 2020

An enzyme-linked immunosorbent assay was developed for the detection of antibodies to influenza type C. Based on replicate testing it was decided that an increase of more than three times the standard error of the mean from one serum specimen to the next represented a significant increase in antibody content. After removal of potentially chicken egg albumin antibodies, the test appeared to be more sensitive for the detection of rises in antibody levels than was hemagglutination inhibition. In some cases, heat treatment of the serum before use in the enzyme-linked immunosorbent assay increased the readings. The strains C/AA/1/59 and C/NJ/1/76 were used in a pilot epidemiological study of influenza C infection in Tecumseh, Mich. Sera tested were collected from autumn of 1976 to autumn of 1978. The overall incidence rate for influenza C infection in the 2-year period was 7.8%. Most cases occurred in children aged 5 to 9 years, and the rates decreased rapidly with increasing age. There appeared to be no relationship to influenza C infection with influenza A or B coinfection. All 17 influenza C infections observed occurred during the 1976 to 1977 respiratory disease season. This indicates that type C virus may not occur endemically, but may exhibit year-to-year variation in infection frequency, as is the case with types A and B.
Extraction of group A streptococcal M protein with nitrous acid
Authors: Hafez K , El Kholy A M , Facklam R R
Published: January 2020

Specific precipitating and opsonic neutralizing antigens were identified in dilute-nitrous acid extracts of group A streptococci. This was done by decreasing the temperature and time of exposure of the streptococcal cells to the nitrous acid. Ninety percent of 31 strains of group A streptococcal dilute-nitrous acid extracts formed precipitin lines of identity with conventional Lancefield extracts of the same group A streptococci.
Comparison of anticomplement immunofluorescence and fluorescent antibody-to-membrane antigen tests for determination of immunity status to varicella-zoster virus and for serodifferentiation of varicella-zoster and herpes simplex virus infections
Authors: Gallo D , Schmidt N J
Published: January 2020

The anticomplement immunofluorescence (ACIF) test was compared with the fluorescent antibody-to-membrane antigen (FAMA) test for determining varicella-zoster virus antibody levels as a measure of varicella-zoster virus immunity status. The ACIF test was found to be comparable to the FAMA test in sensitivity and could be used for examining sera at low dilutions of 1:2 and 1:4. In addition, the ACIF method proved to be a more economical procedure in terms of antigen required and personnel time necessary to perform the test. Heterologous varicella-zoster virus antibody titer rises were demonstrated by the FAMA test with 10 serum pairs from patients with clinically diagnosed genital herpes simplex virus infection, indicating that the FAMA test is no more suitable than other serological methods for serodifferentiation of those herpes simplex virus and varicella-zoster virus infections in which antibody increases occur to both antigens.
Hospital cluster epidemic with Morganella morganii
Authors: Tucci V , Isenberg H D
Published: January 2020

A cluster epidemic of 13 Morganella morganii infections involving 11 patients occurred over a 3-month period in 1977. This epidemic was unusual in that it involved four services and five hospital floors. The outbreak was effectively terminated when strict asceptic techniques were reinforced.
Infection of a brain abscess of Mycoplasma hominis
Authors: Payan D G , Seigal N , Madoff S
Published: January 2020

Persistent fever in a young man after evacuation of a subdural hematoma caused by a depressed skull fracture made it necessary to carry out a computerized tomographic exam of the head that demonstrated a left frontal lobe brain abscess. Mycoplasma hominis was recovered from this abscess as the sole infecting organism. Serial computerized tomographic scans showed resolution after aspiration and antibiotic therapy.
Effects of physiol and chemical factors on the viability of Mycobacterium paratuberculosis
Authors: Richards W D
Published: January 2020

Alternative methods of storing bovine fecal specimens for delayed culture of Mycobacterium paratuberculosis was studied. Significant (P less than 0.05) losses of viability were sustained by storage at 23 degrees C for 10 days and by treatment with 0.03 Zephiran for 4 and 10 days. Losses were moderate after storage at -70 degrees C for 15 weeks but significant (P greater than 0.05) after storage at 23 degrees C for 4 days. The alternative methods were compared with the standard method of processing specimens upon receipt and after 2 days in transit. Fecal specimens from 18 cattle were cultured.
Valuable of terminal subcultures from negative BACTEC blood culture bottles
Authors: Araj G F , Hopfer R L , Wenglar M , Fainstein V
Published: January 2020

Terminal subcultures from 5,354 negative BACTEC blood culture bottles did not significantly improve the detection of positive cultures. Only 15 of the 545 total isolates were recovered from the terminal subcultures. All 15 of these isolates were either considered contaminants or had been previously detected.
Mycobacterium thermoresistibile: a new pathogen for humans
Authors: Weitzman I , Osadczyi D , Corrado M L , Karp D
Published: January 2020

The first evidence of the potential pathogenicity of Mycobacterium thermoresistibile is presented. This mycobacterium, initially identified as Mycobacterium gordonae, was isolated repeatedly from sputum, a bronchoscopy specimen. and later, an open lung biopsy. The distinctive characteristics are described, including the unique ability of the organism to grow at 52 degrees C.
Antigenic Scheme of
Citrobacter koseri
Authors: Sechter Iancu , Altmann Gideon , Cahan David , Braunstein Isidor , Gerichter C. B.
Published: January 2020

An antigenic scheme, based on the determination of 17 somatic and 9 flagellar antigens, is proposed for
Citrobacter koseri
. Seven of the flagellar antigens constituted the specific phase (a through g), and the others (1 and 2) were nonspecific. Of the 238 theoretically possible serotypes, 48 were identified among 680 cultures examined.
Evaluation of the B-D urine culture kit
Authors: Guenther K L , Washington J A
Published: January 2020

Split samples of urine transported to the laboratory at 5 degrees C and in a boric acid-glycerol-sodium formate preservative (B-D Urine Culture Kit; Becton, Dickinson & Co.) were cultured immediately and, in the case of preserved urine, after 24 and 48 h of storage at 25 degrees C. Agreement between the results for cultures of specimens originally yielding greater than 10(5) colony-forming units (CFU) per ml and the results for urine preserved for 24 and 48 h was 85 and 71%, respectively. One-third of the specimens originally yielding 10(4) to 10(5) CFU per ml yielded less than 10(4) CFU per ml after 24 h of storage in preservative. Provided greater than 10(4) CFU per ml in specimens preserved for up to 24 h is regarded as equivalent to greater than 10(5) CFU per ml in original urine specimens, agreement of results was greater than 90%.
Characterization of biochemically atypical Vibrio cholerae strains and designation of a new pathogenic species, Vibrio mimicus
Authors: Davis B R , Fanning G R , Madden J M , Steigerwalt A G , Bradford H B , Smith H L , Brenner D J
Published: January 2020

Biochemically atypical strains classified as Vibrio cholerae were characterized by biochemical reactions, serology, antibiotic susceptibility testing, and deoxyribonucleic acid relatedness. Strains with the following atypical reactions were shown to be V. cholerae: mannose negative, mannitol negative, lysine decarboxylase negative, no growth in the presence of 5% NaCl, salicin and cellobiose positive. Sucrose-negative strains were shown to constitute a new species, Vibrio mimicus, whose type strain is 1721-77 (ATCC 33653). In addition to its negative sucrose reaction, V mimicus was differentiated from V. cholerae by its negative Voges-Proskauer, corn oil, and Jordan tartrate reactions and by its sensitivity to polymyxin. V. mimicus was isolated from shellfish and water, as well as from human diarrheal stools and ear infections. Most strains were typable with antisera against V. cholerae. Strains from three serogroups produced either a heat-labile or a heat-stable enterotoxin.
Detection of rubella antibodies by hemagglutination inhibition, indirect fluorescent-antibody test, and enzyme-linked immunosorbent assay
Authors: Zartarian M V , Friedly G , Peterson E M , de la Maza L M
Published: January 2020

Using hemagglutination inhibition (HAI) as a reference method, 292 (40 nonimmune, 252 immune) human serum samples were tested by indirect fluorescent antibody (IFA) and enzyme-linked immunosorbent assay (ELISA) for immune status and quantitation of rubella antibodies. The overall agreement with HAI for immune status was 99.7% (291/292) with IFA and 98.6% (288/292) with ELISA. Two specimens (0.7%, 2/292), negative by HAI, were equivocal by ELISA. Initially a 6.5% (19/292) overall disagreement was obtained for immune status evaluation between HAI and IFA, which was reduced to 0.3% (1/292) upon repeat testing. All of these samples were near the immune/nonimmune cutoff point (95 samples), reflecting an initial disagreement of 20% (19/95) in this category (HAI titers less than 1:20). Likewise, an initial overall disagreement of 4.5% (13/292) was obtained between HAI and ELISA which was reduced to 0.7% (2/292) upon repeated testing. Eleven of the 13 samples were near the immune/nonimmune cutoff point, reflecting an initial disagreement of 11.6% (11/95) with sera having an HAI antibody titer of less than 1:20. Quantitation of rubella antibodies by IFA showed an overall correlation with HAI of 86.6% within less than twofold titer and 99.3% within less than fourfold titers. In testing the ability of ELISA to quantitate antibody, a correlation coefficient (r) of 0.996 was obtained by plotting the measured average optical density (405 nm) of ELISA against the corresponding log of HAI titer. Both IFA and ELISA showed good correlation with HAI for immune status evaluation and for quantitation of rubella antibodies. Technically the HAI was the most cumbersome to perform, whereas IFA was the least technically demanding. Originally, 308 samples were tested; 16 samples (5.2%) could not be evaluated by IFA because of a high level of nonspecific fluorescence. The strict requirement of controlling the temperature range (23 to 24 degrees C) during substrate hydrolysis proved to be a problem with the ELISA test in our laboratory.
Identification of clinically significant Mycobacterium fortuitum complex isolates
Authors: Silcox V A , Good R C , Floyd M M
Published: January 2020

Recent outbreaks of nosocomial infections caused by organisms identified as the Mycobacterium fortuitum complex suggest that species and subspecies identification is epidemiologically important. In a study of 170 strains, M. fortuitum was differentiated from M. chelonei by nitrate reduction and iron uptake. M. fortuitum was further divided into biovariant fortuitum, biovar peregrinum, and an unnamed third biovar by inositol and mannitol utilization. M. chelonei was further divided into subsp. chelonei, subsp. abscessus, and an unnamed subspecies by tolerance to 5% sodium chloride, utilization of mannitol and sodium citrate, and uptake of iron.
Evaluation of acridine orange stain for detection of Trichomonas vaginalis in vaginal specimens
Authors: Greenwood J R , Kirk-Hillaire K
Published: January 2020

Vaginal exudates from 105 patients were examined by direct wet-mount microscopy and acridine orange stain for the presence of Trichomonas vaginalis. Both procedures demonstrated greater than 90% agreement in both sensitivity and specificity. When specimens can be examined immediately after collection, it appears that wet-mount microscopy is almost as sensitive as acridine orange staining for detection of T. vaginalis.
Serum cryptococcal antigen determination in the presence of rheumatoid factor
Authors: Eng R H , Person A
Published: January 2020

Sera from nine patients with cryptococcal infections and from four with rheumatoid arthritis and positive rheumatoid factor were examined for the presence of cryptococcal capsular antigen by the latex agglutination method. Ethylenediaminetetraacetic acid-heat treatment of the sera before testing possibly increased sensitivity as compared with the untreated sera, and the interfering rheumatoid factor activity was eliminated.
Prevalence of antibodies to Legionella pneumophila in animal populations
Authors: Collins M T , Cho S N , Reif J S
Published: January 2020

We examined more than 2,800 human and animal sera for antibodies to four serogroups of Legionella pneumophila by using the microagglutination test. Antibody titers of greater than or equal to 1:64 were considered positive. The occurrence of positive equine sera (31.4%) was significantly higher than the occurrence of positive sera in cattle (5.1%), swine (2.9%), sheep (1.9%), dogs (1.9%), goats (0.5%), wildlife (0%), and humans (0.4%). The highest titer measured in horses was 1:512. The occurrence of positive sera in horses was related directly to age. In horses less than or equal to 1, 2 to 3, 4 to 7, 8 to 12, and greater than or equal to 13 years old, the percentages of positive sera were 0, 10.1, 30.3, 44.9 and 58.1%, respectively. When we compared age-specific serogroup-specific rates in horses from Colorado and Pennsylvania, we found differences. With horses 8 to 12 and greater than or equal to 13 years old, there was a significantly higher (P less than 0.05) occurrence of sera that reacted to serogroups II and III in horses from Pennsylvania. Of 242 positive sera, 43.8% reacted to a single serogroup (serogroup III or I most commonly), and 56.2% reacted to multiple serogroups (serogroups II and III or serogroups I, II, and III most commonly). A high percentage of seropositive horses suggested that horses are commonly infected with L. pneumophila or related organisms, and the age-specific rates of occurrence indicated that infection was related directly to duration of exposure. A definitive demonstration of equine infection will depend on isolation of the agent and repetition of this serological study with antigens obtained from organisms isolated from horses.
Hippurate hydrolysis by and triphenyltetrazolium tolerance of Campylobacter fetus
Authors: Luechtefeld N W , Wang W L
Published: January 2020

A rapid test of hippurate hydrolysis and a test of tolerance to triphenyltetrazolium chloride (TTC) were studied in 315 strains of Campylobacter fetus subsp. jejuni to determine their usefulness for biotyping this organism and for distinguishing it from C. fetus subsp. intestinalis. Of the 315 strains tested, 84% hydrolyzed hippurate and 97% were resistant to TTC. Ability to hydrolyze hippurate was seen in 99% of 155 human isolates, 75% of 60 avian isolates, 100% of 41 cattle and dog isolates, 84% of 31 zoo mammal isolates, and none of 28 hog isolates. Resistance to 400 micrograms of TTC per ml was seen in 97% of the human isolates, 95% of the avian isolates, and 100% of the mammalian isolates (other than human). In no case did any of the 315 isolates of C. fetus subsp. jejuni show both lack of ability to hydrolyze hippurate and sensitivity to TTC. In contrast, all 18 strains of C. fetus subsp. intestinalis failed to hydrolyze hippurate and were sensitive to TTC. These two tests may be useful to distinguish between C. fetus subsp. jejuni and subsp. intestinalis and also to biotype strains of C. fetus subsp. jejuni.
Recovery of Pseudomonas aeruginosa colonial dissociants on a protease detection medium
Authors: Janda J M , Sheehan D J , Bottone E J
Published: January 2020

Dialyzed brain heart infusion-skim milk agar medium facilitated the recovery of colonial dissociants of Pseudomonas aeruginosa. Differences in colonial morphology as well as in proteolytic activity were readily visualized, thus permitting facile isolation of segregating colony types for further biochemical, serological, and susceptibility studies.
Production of K88, K99, and 987P antigens by Escherichia coli cultured on synthetic and complex media
Authors: Francis D H , Remmers G A , DeZeeuw P S
Published: January 2020

A synthetic medium (E agar) containing glucose and citric acid as the only organic nutrients was found superior to blood agar, Minca-IsoVitaleX (BBL Microbiology Systems, Cockeysville, Md.) agar and broth, and tryptic soy broth (without glucose) for promoting expression of K99 antigen by Escherichia coli strains isolated from diarrheic calves and piglets.
Serogrouping of beta-hemolytic streptococci from throat swabs with nitrous acid extraction and the Phadebact streptococcus test
Authors: Slifkin M , Gil G M
Published: January 2020

A direct extraction of the antigen of group A beta-hemolytic streptococci from 373 throat swabs was done with a microtechnique of the nitrous acid extraction-Phadebact coagglutination method. The technique yielded a 96% agreement with the results obtained by a standard throat culture method in which the Phadebact grouping procedure with overnight broth supernatants was employed.
Comparison of the AutoMicrobic system and a conventional tube system for identification of nonfermentative and oxidase-positive gram-negative bacilli
Authors: Johnson J E , Brinkley A W
Published: January 2020

The AutoMicrobic system (AMS) Enterobacteriaceae-plus Biochemical Card was developed to identify a select group of 10 species of glucose-nonfermentative and oxidase-positive fermentative gram-negative bacilli. In this study, 159 nonenteric clinical isolates were identified by the AMS and conventional tube biochemicals based on E. O. King's (Centers for Disease Control) identification schema. The AMS properly identified 96.7% (117 of 121) of isolates whose taxa were included in the AMS data base. Of 38 isolates (94.7%) in which taxa were not included in the data base, 36 were correctly called unidentified organisms. A principal advantage of the AMS is the automated identification of frequently isolated nonenterics in a period of only 8 to 13 h. The AMS, with the use of the Enterobacteriaceae-plus Biochemical Card appears to be a rapid and accurate system for the identification of the most commonly isolated nonfermentative and oxidase-positive fermentative gram-negative bacilli.
Use of arginine aminopeptidase activity in characterization of arginine-utilizing mycoplasmas
Authors: Ball H J , Neill S D , Reid L R
Published: January 2020

The aminopeptidase activity of arginine-utilizing mycoplasmas was investigated with 20 aminoacyl beta-naphthylamide substrates. High levels of arginyl-beta-naphthylamide hydrolysis were demonstrated in 6 of 11 species when extracts of concentrated washed organisms were used. Relatively low arginine aminopeptidase activity was demonstrated with similar extracts from 22 species not utilizing arginine. The high level of arginine aminopeptidase activity could also be demonstrated with unwashed, unconcentrated samples of the same 6 species and also with Mycoplasma arthritidis. The procedure for preparing the extract of M. arthritidis appeared to remove the arginine aminopeptidase activity which was demonstrated to be present in the untreated culture. Fluorogenic and chromogenic tests were developed whereby this distinctive arginine aminopeptidase activity could be demonstrated within 4 h with the use of small volumes of broth culture (10 microliter) or single colonies, thus providing a rapid test for early characterization of some Mycoplasma species.
Enzyme immunoassay for direct detection of influenza type A and adenovirus antigens in clinical specimens
Authors: Harmon M W , Pawlik K M
Published: January 2020

Detection of viral antigens in specimens without prior cultivation in cell culture provides the most rapid method for specific viral diagnosis. A solid-phase, double-antibody enzyme immunoassay was developed for this purpose and tested with clinical specimens containing influenza type A and adenovirus. Polystyrene microtiter wells were the solid phase and were coated with virus-specific guinea pig immunoglobulins. Specimens were added, and bound viral antigens were detected by addition of virus-specific rabbit immunoglobulins followed by enzyme-labeled goat antirabbit immunoglobulin G. Two methods of labeling goat anti-rabbit immunoglobulin G with horseradish peroxidase were investigated: covalent attachment and a noncovalent, immunological binding of antibody to enzyme, the peroxidase-antiperoxidase method. Both methods of labeling resulted in assays that could detect 10(3.5) 50% tissue culture infectious doses of influenza type A and 10(3.8) 50% tissue culture infectious doses of adenovirus. Equal sensitivity was noted with alkaline phosphatase-labeled goat anti-rabbit immunoglobulin G. An increase in sensitivity of three- to sixfold was achieved when virus-specific rabbit immunoglobulins and conjugate were diluted in 1% gelatin. The solid-phase, double-antibody enzyme immunoassay detected influenza type A and adenovirus in isolation-positive clinical specimens with 53% (21/40) and 62% (13/21) efficiency, respectively. The solid-phase, double-antibody enzyme immunoassay has considerable potential as a practical and rapid method for detection of respiratory viral antigens in nasal wash and throat swab specimens. For optimal value, however, greater sensitivity than was provided by the present methods is desirable.
Dark-field microscopy of human feces for presumptive diagnosis of Campylobacter fetus subsp. jejuni enteritis
Authors: Paisley J W , Mirrett S , Lauer B A , Roe M , Reller L B
Published: January 2020

To determine the value of direct dark-field microscopy for diagnosing enteritis due to Campylobacter fetus subsp. jejuni, we examined 1,377 human fecal specimens for bacteria with typical Campylobacter darting motility, leukocytes, and erythrocytes. Eighty-four specimens (6.1%) grew C.fetus subsp. jejuni. Of the 48 specimens showing Campylobacter motility, 30 (62%) grew C. fetus subsp. jejuni. The sensitivity, specificity, and predictive value of observing Campylobacter motility were 36%, 99%, and 62%, respectively. The predictive value of detecting Campylobacter motility was improved if the specimens were diarrheal (23 of 31, 74%), leukocytes were present (25 of 33, 76%), erythrocytes were present (22 of 27, 81%), or if all of the above findings were present (18 of 20, 90%). The sensitivity of detecting Campylobacter darting motility was highest if specimens were examined within 2 h of arrival in the laboratory (15 of 30, 50%) as opposed to after 2 h (15 of 53, 28%; P less than 0.01). Prompt dark-field microscopic examination of diarrheal stool specimens is valuable for the presumptive diagnosis of Campylobacter enteritis.
Hemadsorption immunosorbent technique for determination of mumps immunoglobulin M antibody
Authors: van der Logt J T , Heessen F W , van Loon A M , van der Veen J
Published: January 2020

We used hemadsorption immunosorbent technique (HIT) to detect mumps immunoglobulin M (IgM) antibody. IgM from human sera was adsorbed into anti-human IgM-coated wells in plates, and mumps-specific IgM was detected by adding mumps virus hemagglutinin and guinea pig erythrocytes consecutively. Specific IgM-positive sera showed hemadsorption, whereas negative sera showed hemagglutination. All 81 patients with current mumps infections tested showed mumps-specific IgM antibody, with titers ranging from 160 to 327,680. In most cases IgM antibody was already present on day 1 or 2 after the onset of illness. IgM antibody persisted for 6 to 10 weeks. Of 57 patients with acute respiratory illnesses caused by parainfluenza virus, 5 showed cross-reactions in the hemadsorption immunosorbent technique assay for mumps IgM. The hemadsorption immunosorbent technique assay is specific for the IgM class of antibody and avoids false-positive results due to rheumatoid factor. This test is an efficient and sensitive method for rapid and early diagnosis of mumps infections.
Characterization of human serum strain-specific antihemagglutinin antibody to A/Port Chalmers/73 (H3N2) influenza virus by radioimmunoprecipitation assays
Authors: Six H R , Kasel J A , Cate T R
Published: January 2020

We performed radioimmunoprecipitation assays in which iodinated preparations of A/Port Chalmers/73 (A/PC/73) hemagglutinin were used as the test antigens and high concentrations of unlabeled A/Hong Kong/68 viral protein were used to inhibit the binding of cross-reactive antibodies to quantitate strain-specific antibody responses in postvaccination sera. Strain-specific antibodies comprised 8 to 48% (mean, 20%) of the total A/PC/73 antigen-binding capacity of the sera tested. Competition radioimmunoprecipitation assays in which disrupted preparations of purified whole virus representative of several of the H3N2 variants were used indicated that the A/PC/73 strain-specific antibody that was present after adsorption of serum by A/Hong Kong/68 antigen was capable of reacting with A/England/72 and A/Victoria/75 hemagglutinins, but generally with lower avidity than with A/PC/73 hemagglutinin. A comparison of the A/PC/73 antibody titers measured by radioimmunoprecipitation and hemagglutination inhibition tests before and after adsorption with A/Hong Kong/68 whole virus suggested that cross-reactive and strain-specific antibodies were comparable in efficiency of inhibiting viral hemagglutination. These data indicated that vaccines containing later variants within a subtype could induce antihemagglutinin antibodies of restricted specificity, but that these antibodies may not be directed against unique antigenic determinant(s).
Detection of immunoglobulin G antibody to purified protein derivative in patients with tuberculosis by radioimmunoassay and enzyme-linked immunosorbent assay
Authors: Zeiss C R , Radin R C , Williams J E , Levitz D , Phair J P
Published: January 2020

Sera from patients with active tuberculosis and sera from appropriate control individuals were assayed for immunoglobulin G antibody activity to purified protein derivative by a polystyrene tube radioimmunoassay and an enzyme-linked immunosorbent assay. Both assays showed a marked increase in immunoglobulin G antibody activity in patients with active tuberculosis. There was no overlap between the values for the patient group and the values for the purified protein derivative skin test-positive control individuals. The replication of these assays was excellent, and both could provide quantitative measurements of immunoglobulin G antibody activity to purified protein derivative antigen within 24 h. These techniques have potential as rapid diagnostic aids in evaluating patients with suspected active tuberculosis.
Solid-phase fluoroimmunoassay for treponemal antibody
Authors: Stevens R W , Schell R F
Published: January 2020

An objective, solid-phase fluoroimmunoassay for treponemal antibody was developed with a lysate of virulent Treponema pallidum (Nichols strain) adsorbed on cellulose acetate disks. A probe containing both the antigen and control disks is inserted successively into a serum specimen dilution, a buffer rinse, fluoroscein isothiocyanate-conjugated goat anti-human immunoglobulin G, and a second buffer rinse. Fluorescence signal units are measured with a fluorometer. To establish test calibration curves, the corrected fluorescence values (antigen disk minus control) of reference sera are plotted against indirect fluorescent treponemal antibody test titers. The corrected fluorescence values obtained for 62 sera reactive in the fluorescent treponemal antibody absorption test ranged from 64 to 178; values for 66 nonreactive sera ranged from 20 to 46. Thus, the solid-phase fluoroimmunoassay for treponemal antibody clearly separated specimens from patients with documented primary, secondary, or latent disease from fluorescent treponemal antibody absorption-nonreactive sera. The test is technically simple and produces an objective quantitative result.
Enzyme-linked immunosorbent assay for detection of antibody to varicella-zoster virus
Authors: Shanley J , Myers M , Edmond B , Steele R
Published: January 2020

Primary varicella-zoster virus (VZV) infection is a serious illness in immunocompromised individuals, and a rapid, sensitive, and reliable assay to identify high-risk VZV-susceptible patients would be clinically useful. An enzyme-linked immunosorbent assay (ELISA) for antibody to VZV was compared with the fluorescent antibody-to-membrane antigen (FAMA) assay and found to be similar in both sensitivity and specificity. The antibody titers determined by both assays were also similar. The absence of antibody detected by ELISA correlated with susceptibility to VZV infection. Because it is simple to perform and has equivalent sensitivity to FAMA, ELISA should be useful for VZV antibody testing in diagnostic and research laboratories.
Evaluation of Phadebact and Streptex Kits for rapid grouping of streptococci directly from blood cultures
Authors: Wellstood S
Published: January 2020

The Phadebact Streptococcus Test and the Streptex Test kits were evaluated for grouping streptococci directly from blood cultures. Pellets of bacteria obtained from centrifuged samples of positive blood cultures were inoculated into Todd-Hewitt broth for 2- and 4-h Phadebact tests and into pronase for Streptex tests. Hemolysis was determined after pipetting a portion of each pellet into cuts made in blood agar plates incubated anaerobically for 2 to 6 h. Serological groups were also determined from colonies of the 137 strains of streptococci used in the study by the Lancefield precipitin method. Of the 126 strains tested by the 4-h Phadebact method, 120 (95.2%) agreed with Lancefield groupings, and 133 (97.1%) of the 137 strains tested by Streptex were in agreement. In contrast, only 31 of 55 strains (56.4%) were correctly identified by the 2-h Phadebact method. Misidentifications were related to multiple agglutinations and weak agglutinations in homologous antisera. Group A isolates were most frequently misidentified by all of the test methods. Hemolysis was determined within 4 h for 92.7% of the isolates and within 6 h for the remaining strains. Although the 4-h Phadebact procedure and the Streptex procedure were comparable in overall accuracy, cost, and technologist time, Streptex was the method of choice for direct groups. Results were available within 75 min for the Streptex procedure compared with 4 h for the Phadebact method. Because few cross-reactions occurred, agglutination responses were clearer and easier to interpret. Results from 2-h Phadebact tests were not satisfactory, and this method is not recommended.
Unheated serum reagin test as a quantitative test for syphilis
Authors: Pettit D E , Larsen S A , Pope V , Perryman M W , Adams M R
Published: January 2020

The unheated serum reagin (USR) test, a standard qualitative test for syphilis, was evaluated for use as a quantitative test for the serodiagnosis of syphilis and as a means of determining the effectiveness of treatment. Tests were performed on 664 syphilitic sera from treated and untreated patients in the primary, secondary, and latent stages of the disease. Also included were 95 false-positive sera and 36 sera from presumably normal donors. The Venereal Disease Research Laboratory slide and rapid plasma reagin 18-mm circle card tests were used as a basis for comparison with the USR test. Results of the USR quantitative test paralleled the Venereal Disease Research Laboratory and rapid plasma reagin card quantitative tests with approximately 84% agreement. The advantages of the USR test make the findings of this study significant in that: (i) less technical manipulation is required to perform the USR test than the Venereal Disease Research Laboratory slide test; (ii) no labor cost is incurred for daily Venereal Disease Research Laboratory antigen preparation; and (iii) the USR antigen is less expensive than the rapid plasma reagin card tests antigen.
Development of a selective medium for detection and enumeration of Actinomyces viscosus and Actinomyces naeslundii in dental plaque
Authors: Zylber L J , Jordan H V
Published: January 2020

A selective medium (CFAT) was developed for the detection and enumeration of Actinomyces viscosus and Actinomyces naeslundii in dental plaque. Neutral acriflavin and potassium tellurite were used in combination with the known selective agents cadmium and fluoride to eliminate most of the competing plaque flora. Composition of CFAT per liter was as follows: Trypticase soy broth (BBL Microbiology Systems), 30 g; glucose, 5 g; agar, 15 g' cadmium sulfate, 13 mg; sodium fluoride, 85 mg; neutral acriflavin, 1.20 mg; potassium tellurite, 2.50 mg; basic fuchsin, 1.25 mg; defibrinated sheep blood, 50 ml. A. viscosus reference strains of human origin grew on CFAT without reduction in numbers under an atmosphere of 90% air-10% CO2. Animal strains of A. viscosus were inhibited at the level of cadmium in CFAT. Two of six A. naeslundii strains did not grow on CFAT. Improved recovery of A. viscosus and A. naeslundii from dental plaque occurred on CFAT, as compared with two other selective media which contained either cadmium sulfate or sodium fluoride, respectively, as selective agents. CFAT was more selective with regard to much of the extraneous gram-positive flora. Bacterionemia, Neisseria, yeasts, and streptococci were virtually eliminated.
Rapid automated identification of gram-negative bacilli from blood cultures with the AutoMicrobic system
Authors: Schifman R B , Ryan K J
Published: January 2020

Automated identification of gram-negative bacilli directly from blood culture bottles by using the AutoMicrobic System (AMS) was evaluated with a modified procedure for the AMS Enterobacteriaceae-plus nonfermenter identification card. A total of 150 strains were tested (44 clinical and 106 seeded) and compared with a conventional identification procedure. These strains included 107 Enterobacteriaceae and 43 oxidase-positive or glucose-nonfermenting, or both, organisms. AMS identifications on one of these strains were not interpretable owing to equal probability AMS identification values. Of the remaining 149 strains, 138 (92.6%) were correctly identified within 8 to 13 h of the first reading. Of 69 identifications analyzed after 6 h of incubation, 91% were correct. This procedure was found to be rapid, convenient, and nonlabor intensive and is recommended for presumptive identification of gram-negative bacilli in blood cultures.
Evaluation of a rapid inoculum preparation method for agar disk diffusion susceptibility testing
Authors: D'Amato R F , Hochstein L
Published: January 2020

A rapid inoculum preparation method for agar disk diffusion susceptibility testing which does not require incubation before inoculation of Mueller-Hinton plates was compared with the National Committee for Clinical Laboratory Standards (NCCLS) method. A total of 326 fresh clinical isolates were tested, and the NCCLS-recommended quality control organisms were included with each test series. Randomly distributed interpretative changes occurred with 27 (0.8%) of the 3,215 test results for the clinical isolates. The quality control organisms were tested on 29 separate days, and results were consistently within tolerance limits. The rapid method was found to be equivalent to the standard NCCLS method and required less time and expense.
Improved rapid slide agglutination test for presumptive diagnosis of canine brucellosis
Authors: Badakhsh F F , Carmichael L E , Douglass J A
Published: January 2020

A modified rapid slide agglutination test for the presumptive identification of Brucella canis infection in dogs has been developed. The method required mixing 0.1 ml of canine serum with 0.1 ml of 0.2 M 2-mercaptoethanol solution. Equal volumes (0.05 ml) of the treated serum and the B. canis plate antigen were mixed. Agglutination results were read within 2 min. Clinical studies showed 100% agreement between this method and the conventional 2-mercaptoethanol tube agglutination test. Excellent correlation was shown between cultural isolation and the modified rapid slide agglutination test, using sera from experimentally infected dogs.
Identification of immunoglobulin heavy-chain isotypes of specific antibodies of horse 46 group B meningococcal antiserum
Authors: Allen P Z , Glode M , Schneerson R , Robbins J B
Published: January 2020

Hyperimmune horse serum from a single animal (horse 46) immunized with group B (strain B-11) meningococcal vaccine provides a standardized, readily available diagnostic reagent used in primary isolation medium and for serogrouping of meningococci. Identification of the heavy-chain isotypes of specific anticapsular polysaccharide and anti-lipopolysaccharide isolated from horse 46 serum revealed a differential distribution in the occurrence of immunoglobulin classes. Meningococcal anticapsular antibodies of horse 46 serum were restricted predominately to the immunoglobulin M (IgM) class, with only trace amounts of IgGa present, whereas anti-lipopolysaccharide concomitantly produced showed a heterogeneity in its heavy-chain isotypes, consisting of IgM, IgGa, IgGb, moderate amounts of IgB, and a small amount of IgA.
Numerical identification of bacteria with a hand-held calculator as an alternative to code books
Authors: Schindler J , Schindler Z
Published: January 2020

The Hewlett-Packard HP 41C hand-held calculator can be used for the numerical identification of bacteria. The dimensions of the identification matrix are limited to about 30 by 22; however, many groups of clinically important bacteria can be numerically identified by this method. Hand-held calculators can be used as an alternative to code books. At present, these calculators and additional tests can help solve identification problems in profiles not contained in code books.
Problems Associated with Counterimmunoelectrophoresis Assays for Detecting
Clostridium difficile
Toxin
Authors: West Susan E. H. , Wilkins Tracy D.
Published: January 2020

The antitoxins currently used for the detection of
Clostridium difficile
by counterimmunoelectrophoresis react with other
C. difficile
antigens in addition to the toxins produced by the bacterium.
Use of Selective Broth Enrichment to Determine the Prevalence of Multiply Resistant JK Corynebacteria on Skin
Authors: Tompkins Lucy S. , Juffali Fawziyah , Stamm Walter E.
Published: January 2020

Use of a selective broth enrichment procedure disclosed a low prevalence (1%) of multiply resistant JK corynebacteria on the skin of healthy adults.
Identification of Streptococcus pneumoniae by the Phadebact coagglutination test
Authors: Burdash N M , West M E
Published: January 2020

The Phadebact Pneumococcus Test is a coagglutination slide test for the serological identification of Streptococcus pneumoniae. Of 200 alpha-hemolytic streptococcal isolates, coagglutination test results agreed with those of optochin susceptibility and bile solubility in 189 cases, 105 of which were identified as S. pneumoniae by all three methods. The Phadebact test was 100% (113 of 113) sensitive and 98% (85 of 87) specific and was more sensitive than counterimmunoelectrophoresis in detecting the presence of pneumococcal antigen in cerebrospinal fluid. In fluids seeded with known amounts of pneumococcal antigen, it consistently detected lower levels than did counterimmunoelectrophoresis. The test provides a rapid and simple method for the definitive identification of S. pneumoniae.
Evaluation of the Enteric-Tek system for identifying Enterobacteriaceae
Authors: Esaias A O , Rhoden D L , Smith P B
Published: January 2020

The Enteric-Tek wheel (Flow Laboratories), consisting of 14 different biochemical parameters for rapidly identifying Enterobacteriaceae, was evaluated and compared with the conventional method for completely identifying 301 enteric cultures, representing 36 species. The Enteric-Tek system correctly identified 264 (97.8%) of the 270 common or typical strains and 26 (83.9%) of the 31 unusual or atypical strains tested, demonstrating an overall identification accuracy rate of 96.3%. There were 80 (26.6%) correctly identified strains requiring additional tests. Of the 11 (3.6%) misidentifications, 5 (3 Klebsiella and 2 Salmonella strains) were correctly identified at the genus level. When 4,228 individual tests in the Enteric-Tek wheel were compared with the conventional tubed media, 96.4% of the tests agreed; urease, citrate, adonitol, and lactose agreed less than 97%. The Enteric-Tek system was found to be reliable and accurate in producing identifications at the genus and species level within 18 to 24 h.
Species identification of coagulase-negative staphylococcal isolates from blood cultures
Authors: Eng R H , Wang C , Person A , Kiehn T E , Armstrong D
Published: January 2020

Coagulase-negative staphylococci generally are not fully identified, are called Staphylococcus epidermidis, and are considered contaminants when isolated from blood cultures. In a cancer hospital during 6 months, 46 patients had multiple blood cultures (mean, 3.1) which yielded coagulase-negative staphylococci. Species identification of these showed that 10 of the 46 (22%) were not S. epidermidis. Similarly, 96 coagulase-negative staphylococci isolated from only one of multiple blood cultures from patients and thought to be skin contaminants were identified. Of 96 of the staphylococci, 14 (16%) of the latter group were not S. epidermidis. Species found included S. haemolyticus, S. hominis, S. warneri, S. simulans, and S. xylosus. Eight isolates of these species were methicillin resistant, and all eight were mannitol fermenters. The results suggest that these species invasively infect cancer patients with the same frequency at which the species colonize. No one species was identified as being more pathogenic than the others. Routine species identification of coagulase-negative staphylococci from blood cultures of cancer patients contributed little to management except to occasionally distinguish multiple-episode culture contamination by different species from sustained bacteremia with the same species.
Thin-layer chromatography of lipid antigens as a means of identifying nontuberculous mycobacteria
Authors: Brennan P J , Heifets M , Ullom B P
Published: January 2020

The previously described thin-layer chromatography procedure (Brennan et al., J. Clin. Microbiol. 8:374-379, 1978) for identifying serovars of the Mycobacterium avium-M. intracellulare-M. scrofulaceum complex, based on their specific C-mycoside glycopeptidolipid antigens, has now been extended to all 31 known serovars. Photographs of the characteristic pattern of the glycopeptidolipids are presented. Although the procedure is fraught with the difficulties inherent to comparative thin-layer chromatography, it is particularly suitable for the screening of isolates which are not amenable to seroagglutination, such as those which autoagglutinate or for which antisera are not presently available. In this way it was possible to tell whether isolates were of the M. avium-M. intracellulare-M. scrofulaceum complex and whether or not they had previously been recognized. Knowledge of the chemical features of the typing antigens nontuberculous mycobacteria other than M. avium-M. intracellulare-M. scrofulaceum strains also enables us to develop thin-layer chromatography systems for the identification of M. kansasii, M. szulgai, members of the M. gordonae complex, M. terrae, M. xenopi, and M. gastri.
Solid-phase Clq-binding fluorescence immunoassay for detection of circulating immune complexes
Authors: Collins M M , Casavant C H , Stites D P
Published: January 2020

A fluorescence immunoassay for detection of immune complexes bound to solid-phase C1q was developed. The method was standardized by using human aggregated immunoglobulin G (IgG) to simulate immune complexes. A linear relationship existed between the concentrations of the aggregated IgG standards and the resulting fluorescent intensity. The method was found to be reproducible and capable of detecting as little as 10 micrograms of aggregated IgG per ml of heat-inactivated human serum. Antigen-antibody complexes prepared in vitro were detectable from equivalence to moderate antigen excess. Endogenous serum C1q inhibited the binding of aggregated IgG to solid-phase C1q. Pretreatment of test sera with EDTA was ineffective in eliminating this competitive effect. Heating the sera at 56 degrees C alleviated, but did not abolish, interference of endogenous C1q. Elevated levels of immune complexes were detectable in sera fro seven of nine patients wit systemic lupus erythematosus, provided the samples were heat inactivated before testing. Heparin and DNA were also found to interfere with the detection of aggregated IgG added to human serum. Assay values were falsely decreased due to competitive inhibition by these anions. Lipopolysaccharides from a variety of bacterial preparations produced no detectable interference. A comparative study was conducted on samples that had previously been tested by fluid-phase C1q-binding radioimmunoassay. The two methods were concordant in assigning normal or elevated levels of immune complexes in 70% of the samples tested. This solid-phase fluorescence immunoassay is proposed as a possible alternative to radioimmunoassay for the detection of circulating immune complexes.
Rapid identification of Clostridium difficile by toxin detection
Authors: Chang T W , Gorbach S L
Published: January 2020

Rapid identification of Clostridium difficile in a stool specimen could be accomplished within 24 h by detection of toxin elaborated in an agar or broth culture containing cycloserine and cefoxitin. Broth culture seemed to give a more rapid and sensitive result than the agar plate culture. For cultivation of C. difficile in stool, we recommend the use of chopped meat broth and blood agar plate, the former for toxin detection in 1 to 2 days and the latter for colonial morphology and isolation of a pure culture.
New bacteriophage typing system for Yersinia enterocolitica, Yersinia kristensenii, Yersinia frederiksenii, and Yersinia intermedia: correlation with serotyping, biotyping, and antibiotic susceptibility
Authors: Baker P M , Farmer J J
Published: January 2020

Yersinia enterocolitica is listed as a single species in Bergey's Manual of Determinative Bacteriology, but has recently been split into "true" Y. enterocolitica, Y. kristensenii, Y. intermedia, and Y. frederiksenii. From 48 bacteriophages isolated from raw sewage, 24 were chosen as being the most useful for differentiating strains within the four Yersinia species. The composite set of 24 phages typed 92% of 236 Y. enterocolitica strains, 100% of 16 Y. kristensenii strains, 97% of 29 Y. frederiksenii strains, and 90% of 20 Y. intermedia strains. The most common phage type in any of the groups contained 22% of the strains tested, but most of the phage types contained greater than 5% of the strains. The new typing schema was tested in three outbreaks of Y. enterocolitica, and the results agreed well with serotyping and epidemiological findings. In the same outbreaks, biotyping (API 20E profiles; Analytab Products, Plainview, N.Y.) and antibiograms were less reliable markers and probably should be used only in conjunction with serotyping or phage typing or both. Caution should be used in identifying cultures of Y. frederiksenii and Y. intermedia with the API 20E system, since the tests at 37 degrees C for L-rhamnose and melibiose fermentation are often delayed past 24 h, which is the cut-off point for the final reading in the API system. There were distinct differences in the susceptibilities of Y. enterocolitica and Y. kristensenii to ampicillin, carbenicillin, and cephalothin, which adds further support for classifying the latter as a separate species.
Arthritis caused by unidentified gram-positive rods in a child with acute lymphocytic leukemia
Authors: Appelbaum P C , Dossett J H
Published: January 2020

A 12-year-old girl with refractory acute lymphocytic leukemia developed arthritis owing to an unidentified gram-positive Corynebacterium-like rod. The infection responded to amoxycillin therapy, but death ensued owing to the underlying leukemic condition.