bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzyme immunoassay for detection of human immunodeficiency virus antigens in cell cultures
Authors: Viscidi R , Farzadegan H , Leister F , Francisco M L , Yolken R
Published: January 2020

A sensitive and specific avidin-biotin enzyme immunoassay that uses immunoreagents from naturally infected individuals was formulated for the detection of human immunodeficiency virus (HIV) antigens. A total of 500 cell culture samples from 111 cultures were tested in this assay and in a reverse transcriptase (RT) assay. Of 353 samples that were positive in the immunoassay, 174 were positive and 179 were negative in the RT assay. The specificity of the immunoassay results was supported by the failure of samples to react with nonimmune serum, by the ability of an anti-HIV type 1 monoclonal antibody to block the reactivity of selected samples, and by the appearance of RT activity in samples drawn from some cultures after a longer period of cultivation. HIV antigens were detected in 174 of 176 RT-positive samples (sensitivity, 98.9%). A comparison of the kinetics of antigen production and RT activity revealed that detectable antigen levels frequently preceded the appearance of RT activity. Thus, 50% of virus-containing cultures were identified within 9 days by immunoassay compared with 14 days by RT assay. In addition, RT activity was often detected intermittently in cultures sampled on several days, whereas antigen levels did not decline after initial appearance. Enzyme immunoassays for HIV antigen detection that use easily obtained reagents and simple technologies could facilitate laboratory and clinical research which requires cultivation of viruses.
Enzyme-linked immunosorbent assay of antibody to group A Streptococcus-specific C carbohydrate with trypsin-pronase-treated whole cells as antigen
Authors: Todome Y , Ohkuni H , Yokomuro K , Kimura Y , Hamada S , Johnston K H , Zabriskie J B
Published: January 2020

We describe the measurement by enzyme-linked immunosorbent assay of antibody to group A Streptococcus C carbohydrate in immunized rabbits and human sera, with trypsin-pronase-treated group A streptococcal whole cells used as the antigen. The optimal concentration of the enzyme-treated whole cells used to coat the wells was 2 x 10(7) cells per well. Rabbit antiserum diluted to 1:12,800 and human serum diluted to 1:1,000 were found to be the optimal concentrations for antibody measurement. Antibody that reacted with enzyme-treated whole cells in rabbit antiserum was absorbed with group A streptococcal whole cells, purified C carbohydrate, and N-acetylglucosamine only. Enzyme-treated whole cells did not react with anti-lipoteichoic acid antibody, and rabbit antiserum did not react with lipoteichoic acid. There was a highly significant correlation between the anti-C carbohydrate antibody titrated with enzyme-treated whole cells and that with purified C carbohydrate as antigen. The correlation coefficient for the immunoglobulin M (IgM) antibodies was r = 0.75, and for the IgG antibodies it was r = 0.77. When the IgG antibody titers to the enzyme-treated whole cells of the sera of patients with acute poststreptococcal glomerulonephritis and rheumatic fever were compared with those of sera of healthy individuals, the sera of patients with poststreptococcal sequelae had significantly higher titers than did healthy individuals. Although anti-C carbohydrate antibody in human sera mostly belonged to the IgG2 subclass, there was anti-C carbohydrate antibody that belonged to the IgG3 subclass in a certain percentage of patients with rheumatic fever and acute poststreptococcal glomerulonephritis.
Characterization of an outbreak of Clostridium perfringens food poisoning by quantitative fecal culture and fecal enterotoxin measurement
Authors: Birkhead G , Vogt R L , Heun E M , Snyder J T , McClane B A
Published: January 2020

Published criteria for implicating Clostridium perfringens as the cause of food-poisoning outbreaks include finding a median fecal C. perfringens spore count of greater than 10(6)/g among specimens from ill persons. We investigated a food-poisoning outbreak with the epidemiologic characteristics of C. perfringens-related disease in a nursing home in which the median fecal spore count for ill patients (2.5 X 10(7)/g) was similar to that for well patients (4.0 X 10(6)/g), making the etiology of the outbreak uncertain. All ill and well patients tested had eaten turkey, the implicated food item. C. perfringens enterotoxin was detected by reverse passive latex agglutination in fecal specimens from six of six ill and none of four well patients who had eaten turkey (P = 0.005), suggesting that this organism had caused the outbreak. This investigation suggests that detection of fecal C. perfringens enterotoxin is a specific way to identify this organism as the causative agent in food-poisoning outbreaks.
Plasmid analysis of Borrelia burgdorferi, the Lyme disease agent
Authors: Barbour A G
Published: January 2020

A simple procedure for extraction of plasmid-enriched DNA from borreliae was used in a plasmid analysis of 13 strains of the Lyme disease agent, Borrelia burgdorferi. The extracted DNA was subjected to low-percentage agarose gel electrophoresis and examined either directly by ethidium bromide staining or after hybridization of the plasmids in situ with a DNA probe for the gene encoding the major outer membrane protein OspA. Each isolate had four to seven discernible plasmids of various sizes. Only 2 of the 13 strains had the same plasmid profile. The ospA gene probe hybridized to large plasmids to strains from both North America and Europe. A strain which had been passaged many times was found to have lost two of the six plasmids originally present. These findings indicate the potential usefulness of plasmid analysis as a strain-typing procedure and for identifying possible plasmid-conferred virulence factors.
Cultural and chemical characterization of CDC groups EO-2, M-5, and M-6, Moraxella (Moraxella) species, Oligella urethralis, Acinetobacter species, and Psychrobacter immobilis
Authors: Moss C W , Wallace P L , Hollis D G , Weaver R E
Published: January 2020

We determined phenotypic characteristics, cellular fatty acid composition, and isoprenoid quinone content of representative strains of CDC groups EO-2, M-5, and M-6, Moraxella (Moraxella) species, Oligella urethralis, Acinetobacter species, and Psychrobacter immobilis. All organisms contained ubiquinone with eight isoprene units as the major isoprenolog, but distinct differences were observed in fatty acid composition. Twenty-eight of the original collection of CDC group EO-2 strains were further identified as P. immobilis, EO-2, or EO-3 by distinctive cellular fatty acid profiles, cellular morphology, and pigment production. The cellular fatty acid compositions of M-5 and M-6 were similar but were clearly different from those of other organisms. The genus Acinetobacter was differentiated from other organisms in the study by small amounts of 2-hydroxydodecanoic acid (2-OH-12:0), and P. immobilis was differentiated by small amounts of decanoic acid (10:0) and a branched-chain 17-carbon acid (i-17:0). All Moraxella species were distinguished by small amounts of decanoic acid (10:0) and the absence of i-17:0. M. bovis, M. nonliquefaciens, and some strains of M. lacunata formed a single fatty acid group, while M. osloensis, M. phenylpyruvica, M. atlantae, and other strains of M. lacunata (M. lacunata II) had species-specific fatty acid profiles. O. urethralis differed from Moraxella species by the presence of large amounts (49%) of cis-vaccenic acid (18:1 omega 7c), small amounts (1%) of 3-hydroxyhexadecanoate (3-OH-16:0), and the absence of 10:0 and 3-hydroxydodecanoate (3-OH-12:0). The combined use of chemical data and a small number of conventional tests permitted rapid identification and differentiation of these organisms from each other and from related organisms.
Evaluation of eight methods for identification of pathogenic Neisseria species: Neisseria-Kwik, RIM-N, Gonobio-Test, Minitek, Gonochek II, GonoGen, Phadebact Monoclonal GC OMNI Test, and Syva MicroTrak Test
Authors: Dillon J R , Carballo M , Pauzé M
Published: January 2020

The performance of eight methods in identifying Neisseria species, particularly N. gonorrhoeae, was evaluated. These methods included four rapid carbohydrate utilization tests (Gonobio-Test, Neisseria-Kwik, RIM-N, and Minitek); the Gonochek II, a test which is based on the utilization of chromogenic substrates; and three monoclonal antibody tests (Syva MicroTrak, GonoGen, and Phadebact Monoclonal GC OMNI Test). In all, 182 isolates comprised in six species of Neisseria as well as Branhamella catarrhalis and Moraxella sp. were tested. Cystine-tryptic digest agar supplemented with sugars was included for reference purposes. In the carbohydrate utilization tests, the sensitivity and specificity of the Neisseria-Kwik and Minitek tests for the identification of N. gonorrhoeae were 100%. This compared with sensitivities and specificities, respectively, of 100 and 99.1% for the Gonobio-Test and 99.1 and 100% for cystine-tryptic digest agar sugars and the RIM-N test. The sensitivity and specificity of the Gonochek II test were 99.0 and 86.7%, respectively. Although most test kits did not claim to identify all Neisseria species, in several cases isolates of N. subflava were misidentified or could be misinterpreted as N. gonorrhoeae or N. meningitidis. With the monoclonal reagents, the Syva MicroTrak system was 100% sensitive and 100% specific. The GonoGen test was both 99.1% sensitive and specific, while the Phadebact Monoclonal GC OMNI Test was 99.1% sensitive but 91.2% specific. With this latter test, cross-reactions were observed with strains of B. catarrhalis, N. cinerea, and N. lactamica.
Rapid quantitation of cytomegalovirus and assay of neutralizing antibody by using monoclonal antibody to the major immediate-early viral protein
Authors: Chou S W , Scott K M
Published: January 2020

An overnight assay, based on staining cytomegalovirus-infected cells with monoclonal antibody to the 72,000-molecular-weight major immediate-early viral protein, was compared with a conventional 14-day plaque assay for quantitation of cell-free stocks of cytomegalovirus laboratory strain AD-169 and 20 other clinical strains. Viral titers were quantitatively similar when determined by either method, but centrifugation of monolayers during inoculation enhanced viral infectivity an average of 4.1-fold. When used for scoring neutralizing antibody assays, monoclonal antibody staining yielded titers within one dilution of 14-day plaque-reduction assays in 54 of 56 titrations. Of 21 cytomegalovirus strains, 2 were not recognized by the monoclonal antibody used. Assay with monoclonal antibody offers a rapid and accurate alternative to plaque assays for quantitation or neutralization of cytomegalovirus.
Effects of protein, mucin, and human tears on adherence of Pseudomonas aeruginosa to hydrophilic contact lenses
Authors: Miller M J , Wilson L A , Ahearn D G
Published: January 2020

Pseudomonas aeruginosa isolated from a corneal ulcer was examined for its ability to adhere to hydrophilic contact lenses with adsorbed organic films. Generally, adherence was enhanced by mucin, lactoferrin, lysozyme, immunoglobulin A, bovine serum albumin, and a mixture of these macromolecules. The water content of the lenses also influenced bacterial adherence and protein adsorption. Adherence to lenses coated with human tear films was more complex; both enhanced and inhibited adherence were observed on lenses obtained from different individuals.
Virulence factors of lactose-negative Escherichia coli strains isolated from children with diarrhea in Somalia
Authors: Nicoletti M , Superti F , Conti C , Calconi A , Zagaglia C
Published: January 2020

Lactose-negative Escherichia coli strains were isolated at high frequency from children with diarrhea in Somalia during a 2-year study on diarrheal diseases. Sixty-four of these strains, considered to be a representative sample, were characterized for virulence factors, plasmid profiles, and antibiotic resistance. Of these strains, 5 were recognized as enteroinvasive E. coli (they were serotyped as O135:K-:H-), 6 belonged to classical enteropathogenic E. coli serotypes, 9 were able to adhere to tissue culture cells (of these, 4 showed a pattern of localized adherence and 1 was an enteropathogenic strain), 18 were both adherent and hemolytic, and 8 were simply hemolytic. None hybridized with 32P-labeled heat-labile or heat-stable (a and b) enterotoxin gene probes or produced moderate or high-level cytotoxic effects on HeLa cells. Of the 64 strains examined, 24 produced mannose-resistant hemagglutination with human, chicken, and monkey erythrocytes. One of these was serotyped as O4:K-:H8, and a rabbit O antiserum raised against this strain allowed us to establish that 23 strains had the same O antigen. The 23 O4 strains were hemolytic and were not enterotoxic for rabbit ileal loops, and intact bacteria were able to destroy tissue culture cell monolayers very rapidly. The uniformity of the antibiotic resistance pattern and of the plasmid DNA content, together with the fact that they were isolated in different years and in different children, suggests that the O4 strains must be epidemiologically relevant in Somalia. A possible diarrheagenic role for the adherent-hemolytic E. coli strains is also discussed.
Comparative study of colony hybridization with synthetic oligonucleotide probes and enzyme-linked immunosorbent assay for identification of enterotoxigenic Escherichia coli
Authors: Sommerfelt H , Svennerholm A M , Kalland K H , Haukanes B I , Bjorvatn B
Published: January 2020

On the basis of the published nucleotide sequences of the genes that code for the heat-labile toxin LTh and the heat-stable toxins STaI and STaII of human enterotoxigenic Escherichia coli, a 34-mer and two 33-mer oligonucleotide probes were synthesized. To compare their relative efficacies in the detection and differentiation of enterotoxigenic E. coli, a colony hybridization technique using these probes and a GM1 ganglioside enzyme-linked immunosorbent assay using monoclonal anti-LT and anti-ST antibodies were used with 76 strains of E. coli with known enterotoxin profiles. For further evaluation of probe specificity, the enterotoxigenic bacteria Vibrio cholerae O1 and non-O1 and Yersinia enterocolitica were examined with the colony hybridization technique. The sensitivity of colony hybridization compared favorably with that of GM1 ganglioside enzyme-linked immunosorbent assay, and the two assays showed a high level of concordance in specific detection and differentiation of E. coli with various enterotoxin profiles (kappa = 0.906, P less than 0.00001). The probes did not hybridize with DNAs from strains of V. cholerae O1 or non-O1 or Y. enterocolitica.
Comparison of six serological assays for human immunodeficiency virus antibody detection in developing countries
Authors: Van de Perre P , Nzaramba D , Allen S , Riggin C H , Sprecher-Goldberger S , Butzler J P
Published: January 2020

Three commercially available assays for the detection of human immunodeficiency virus (HIV) antibodies-Vironostika enzyme immunoassay (EIA), Wellcozyme competitive EIA, and JLC Allaman indirect immunofluorescence assay--were tested on 300 serum samples from African subjects with and without HIV-related conditions. Two experimental assays both rapid and simple to perform (Biotech dip stick and Cambridge Bioscience latex agglutination) were also evaluated on the same serum samples. The results were compared with those of a commercial Western blot (WB) (immunoblot) assay from Biotech, used as the reference technique. All assays were tested in the laboratory of the AIDS Project in Kigali, Rwanda. Calculated specificity ranged from 90.8% (dip stick) to 98.6% (Vironostika EIA, Wellcozyme competitive EIA, and Cambridge Bioscience latex agglutination). Sensitivity ranged from 95.2% (Cambridge Bioscience latex agglutination) to 98.0% (Vironstika EIA) and JLC indirect immunofluorescence assay). However, the sensitivity of the latex agglutination test improved to 98.6% after the prozone effect was controlled for by serial twofold dilution of latex agglutination-negative, WB-positive samples. In situations with a high prevalence of HIV infection, any one of these tests can be regarded as an alternative to the more expensive, time-consuming, and difficult WB assay.
Detection of dengue virus type 2 in Aedes albopictus by nucleic acid hybridization with strand-specific RNA probes
Authors: Olson K , Blair C , Padmanabhan R , Beaty B
Published: January 2020

A molecular hybridization technique with radiolabeled, strand-specific RNA probes was developed to detect dengue virus type 2 RNA in pools of infected Aedes albopictus mosquitoes. One infected mosquito in a pool of 25 could be detected, corresponding to a dengue virus type 2 titer of 2.75 log10 50% tissue culture infectious doses.
Routine culture of stool specimens for Yersinia enterocolitica is not a cost-effective procedure
Authors: Kachoris M , Ruoff K L , Welch K , Kallas W , Ferraro M J
Published: January 2020

Cefsulodin-Irgasin-novobiocin (CIN) agar was used to isolate Yersinia enterocolitica from 3,622 stool specimens received in our laboratory during a 1-year period. Seven specimens (0.2%) yielded Y. enterocolitica strains from a total of five patients. The low frequency of Y. enterocolitica isolation observed, coupled with the isolation of this pathogen from three of the five patients by our standard stool examination protocol, leads us to conclude that routine culture of stool specimens on CIN agar is not a cost-effective procedure.
Aerobic and anaerobic bacteriology of purulent nasopharyngitis in children
Authors: Brook I
Published: January 2020

Cultures of aerobic and anaerobic bacteria were obtained from the inferior nasal meatus of 25 children with purulent nasopharyngitis and from 25 controls. Microorganisms were isolated from all specimens. A total of 98 isolates (3.9 per patient), 45 aerobes (1.8 per patient) and 53 anaerobes (2.1 per patient), were isolated in patients with purulent nasopharyngitis. Seventy-three isolates (2.9 per patient), 47 aerobes (1.9 per patient) and 26 anaerobes (1.0 per patient) were found in the controls. The organisms recovered in statistically significantly higher numbers in patients with nasopharyngitis were Streptococcus pneumoniae, Haemophilus sp., Peptostreptococcus spp., Fusobacterium spp., and Bacteroides spp. The organisms recovered in significantly higher numbers in controls were Staphylococcus aureus and Propionibacterium acnes. beta-Lactamase activity was detected in 19 isolates recovered from 15 individuals (9 patients and 6 controls). These findings demonstrate the aerobic-anaerobic polymicrobial flora associated with purulent nasopharyngitis. Further studies are indicated to evaluate the pathogenic role of these organisms in this condition.
Yeast killer toxin-like anti-idiotypic antibodies
Authors: Polonelli L , Morace G
Published: January 2020

Anti-idiotypic antibodies (anti-Ids) were raised in a rabbit against a murine monoclonal antibody (MAb) neutralizing the yeast killer toxin produced by a strain of Pichia (Hansenula) anomala. In an immunodiffusion test, the anti-Ids produced in the rabbit recognized the antigen-binding site of the MAb used as the immunogen (KT4) but not that of another heterologous MAb. The absence of any significant cross-reactivity among the anti-Ids raised in a rabbit for a heterologous MAb suggested that the anti-Ids were highly specific for unique variable-region determinants. Furthermore, the P. anomala killer toxin proved to be competing with anti-Ids for the binding site of MAb KT4. Anti-Ids against the MAb to yeast killer toxin inhibited the growth of Candida albicans, thereby mimicking the effect of the yeast killer toxin. These results suggest that, in some cases, anti-Ids might be useful tools for elucidating structure-function relationships for sensitive cell receptors.
Campylobacter jejuni antibodies in Nigerian children
Authors: Ani E A , Takahashi T , Shonekan R A
Published: January 2020

Titers of complement-fixing (CF) antibody to Campylobacter jejuni were demonstrated in 87 (36.7%) of 237 infants 6 to 15 months old in Jos, Nigeria. Of the total number of children examined, 81 had acute diarrhea and 27 of them (33.3%) were found to have CF antibodies in their serum. The remaining 156 children were asymptomatic, and 60 (38.4%) of them had CF antibodies. In the diarrheal group, 27 of 75 children 6 to 8 months old were CF antibody positive. There was no significant difference in the incidence of CF C. jejuni antibodies in the diarrheal and nondiarrheal infants (P greater than 0.05). Also, infants 9 to 15 months old had a higher incidence of CF antibodies (46.5%) than those 6 to 8 months of age (25%). The data suggest that the infants whose sera were CF antibody positive had had an exposure to C. jejuni. All 33 infants 6 to 8 months of age who had no diarrhea were CF antibody negative.
Catheter-associated Candida utilis fungemia in a patient with acquired immunodeficiency syndrome: species verification with a molecular probe
Authors: Alsina A , Mason M , Uphoff R A , Riggsby W S , Becker J M , Murphy D
Published: January 2020

Candida utilis was cultured from the blood of a patient with acquired immunodeficiency syndrome. The candidemia was apparently associated with catheter implantation. The isolate was identified initially by standard methods and verified by molecular probing. The pattern of actin-specific restriction fragments obtained from the DNA of the isolate, probed with C. albicans actin sequences, corresponded to that of C. utilis. This organism adds to the growing list of Candida species associated with human disease. Molecular probing offers a definitive identification when an unexpected etiological agent is found.
Antibodies reactive with human immunodeficiency virus gag-coded antigens (gag reactive only) are a major cause of enzyme-linked immunosorbent assay reactivity in a blood donor population
Authors: Tribe D E , Reed D L , Lindell P , Kenealy W R , Ferguson B Q , Cybulski R , Winslow D , Waselefsky D M , Petteway S R
Published: January 2020

Normal blood donors were examined for human immunodeficiency virus (HIV)-reactive antibodies with both virus- and Escherichia coli-expressed env- and gag-coded antigens. The frequency of samples from normal (low-risk) donors that were repeatedly reactive with an HIV enzyme-linked immunosorbent assay blood screening test (Du Pont Co.) was 0.6%. Two classes of HIV serological reactivity were identified: a minor env-reactive class (0.03 to 0.06% of donors) and the predominant env-nonreactive gag-reactive class (gag reactive only [GRO]) (0.4 to 0.5% of donors). Assignment of env reactivity was made by a synthetic (recombinant) env enzyme-linked immunosorbent assay and virus immunoblot. Most GRO sera reacted with p15/p17 bands on HIV immunoblot. Antibody specificity in GRO sera was confirmed by competition-binding studies with viral gag and E. coli-expressed p55gag. This study provides independent verification that gag-specific antibodies are present in many env-nonreactive sera. More serological and virological studies of individuals with this antibody pattern should be pursued to determine the origin of these gag-reactive antibodies.
Kinetics of specific immunoglobulins M, E, A, and G in congenital, primary, and secondary cytomegalovirus infection studied by antibody-capture enzyme-linked immunosorbent assay
Authors: Nielsen S L , Sørensen I , Andersen H K
Published: January 2020

Antibody-capture enzyme-linked immunosorbent assay (ELISA) using enzyme-labeled cytomegalovirus (CMV) nuclear antigen is a reliable and easily performed test suitable for routine use. As the serologic response to CMV infection may, however, vary considerably among patients, we have studied the kinetics of CMV-specific immunoglobulin M (IgM), IgE, IgA, and IgG antibodies in 352 sera from 61 patients by using antibody-capture ELISA and complement fixation (CF) tests. In a CMV mononucleosis group (n = 17), most patients had antibodies of all four immunoglobulin classes, but antibody levels decreased rapidly, with half the patients having a borderline-positive or a negative reaction for all classes, except IgG, 2 months after the appearance of symptoms. Twelve patients with a primary CMV infection after renal or bone marrow transplantation also developed all immunoglobulin-class antibodies. In only two patients did CMV IgM and IgE antibodies precede seroconversion of CF antibodies, and in one patient, these antibodies lagged months behind. Most patients had all classes of CMV antibodies, except IgA, for a year or more. Among 10 transplant patients with a secondary CMV infection, 50% had long-lasting IgM antibodies, and very few had IgE or IgA antibodies, but all had IgG antibodies to CMV. In 13 infected infants, the CMV-specific serologic response was also characterized by long-lasting IgM, IgE, and IgG antibodies. Two patients did not develop detectable IgM antibodies, and one of these did not show IgE antibodies either. The IgA response in infants as a whole was lacking; a few, however, were borderline positive. Of the nine acquired immunodeficiency syndrome patients with CMV infection studied during their last year of life, only one had antibodies in all four classes, the rest had only CF antibodies, and all except for one had IgG-class antibodies. All sera studied were also tested against a control antigen produced from noninfected cell nuclei. It was found that some patients developed antibodies to nuclear antigens in parallel with the rise in specific antibodies. The nonspecific antibodies occurred in all four classes, but most often they were of the IgM class. Addition of unlabeled control antigen to the conjugates was not always sufficient to abort this nonspecific reaction.
Subgroups, serotypes, and electrophoretypes of rotavirus isolated from children in Bangui, Central African Republic
Authors: Georges-Courbot M C , Beraud A M , Beards G M , Campbell A D , Gonzalez J P , Georges A J , Flewett T H
Published: January 2020

The subgroups and serotypes of 178 strains of rotavirus isolated from diarrheic and healthy children in Bangui, Central African Republic, during a 27-month period were determined by enzyme-linked immunosorbent assay. The subgroup was determined for 152 of the viral strains, 18.4% being subgroup I and 81.6% being subgroup II. Of the 143 strains which could be serotyped, 71.3% were serotype 1, 15.4% were serotype 2, and 13.3% were serotype 3. Serotypes 1 and 3 were detected throughout the study, while serotype 2 was detected only during 8 months. No serotype exhibited any special epidemiological properties. The serotypes were found to consist of three different electrophoretypes, two long ones (A and B) and a short one (C). All subgroup I, serotype 2 strains presented short electrophoretypes. Strains with identical long electrophoretypes A were either serotype 1 or serotype 3.
Gas-liquid chromatographic analysis of fatty acid methyl esters of Aeromonas hydrophila, Aeromonas sobria, and Aeromonas caviae
Authors: Canonica F P , Pisano M A
Published: January 2020

Clinical isolates of Aeromonas hydrophila, A. sobria, and A. caviae whose fatty acid content had been analyzed by gas-liquid chromatography (GLC) displayed the following qualitatively similar GLC profiles: 12:0, 14:0, 15:0, 16:0, 17:0, 18:0, 16:1, 18:1, a-15:0, a-17:0, and 3-OH 14:0. The 16:0/17:0 area-percentage ratio separated the clinical aeromonads in accordance with their species designations. Aeromonads treated with subminimal inhibitory concentrations of the antibiotic cerulenin displayed the following altered qualitative fatty acid GLC profiles: 12:0, 14:0, 16:0, 18:0, 16:1, 18:1, and 3-OH 14:0. Cerulenin-treated cells failed to reproducibly display detectable levels of all odd-numbered-carbon-chain-length fatty acids observed in untreated cells. Cerulenin-treated cells also exhibited overall increases in 14:0 and 3-OH 14:0 and a decrease in total unsaturated fatty acid content.
In vitro method to differentiate isolates of type III Streptococcus agalactiae from symptomatic and asymptomatic patients
Authors: Maurer J J , Mattingly S J
Published: January 2020

Streptococcus agalactiae (group B streptococci) isolates from infected infants have been demonstrated to have three- to fourfold or higher levels of cell-associated lipoteichoic acid than isolates from asymptomatically colonized infants, suggesting a role for this cell surface polymer in the relative virulence of these organisms. The present study indicates that symptomatic isolates of type III group B streptococci can be readily differentiated from asymptomatic strains by their response to various levels of phosphate in a chemically defined medium (FMC). Both classes of isolates had the same doubling time (TD of 30 to 35 min) in FMC containing 65 mM sodium phosphate. However, levels of phosphate greater than 125 mM distinguished the two classes of strains. Asymptomatic strains pregrown in 65 mM phosphate to the stationary phase rapidly initiated growth at elevated phosphate levels, while symptomatic strains initiated growth only after a prolonged incubation period (greater than 400 min). These results suggest that the physiological growth response of clinical isolates of group B streptococci to phosphate can serve as a diagnostic aid in screening potentially virulent strains in pregnant women and newborn infants.
Comparison of Meritec-Strep with Streptex for direct colony grouping of beta-hemolytic streptococci from primary isolation and subculture plates
Authors: Hamilton J R
Published: January 2020

Meritec-Strep (Meridian Diagnostics, Inc., Cincinnati, Ohio) a coagglutination method, was compared with Streptex (Wellcome Diagnostics, Research Triangle Park, N.C.), a latex agglutination method, for the identification of beta-hemolytic streptococcal groups A, B, C, F, and G by the direct colony method. A total of 124 beta-hemolytic streptococcal isolates were tested, which included 77 from group A, 15 from group B, 10 from group C, 1 from group F, and 21 from group G. All were tested from subculture, and 74 (60%) were also tested from primary isolation plates. For Meritec-Strep, usually one colony was directly applied to the reaction card for testing each grouping reagent, while for Streptex, five colonies were tested after a 1-h extraction process. Complete agreement was obtained for all isolates tested from subculture with the kits. From primary isolation plates, Meritec-Strep correctly identified 97.3% of the isolates compared with 94.6% correctly identified for Streptex. Meritec-Strep produced a false-negative for one group A isolate and positive reactions for group A and F reagents with another group A isolate. A diphtheroid contaminant caused the positive group F reaction. Streptex produced false-negative results for one group A and three group C isolates. Most positive reactions were strong and rapid (less than 30 s) for both kits. The negative test control provided in the individual group A and B kits was nonreactive for all isolates. Meritec-Strep accurately identified isolated colonies of beta-hemolytic streptococci on primary isolation and subculture plates. It provided faster results than Streptex by eliminating the time and manipulation of antigen extraction and needed fewer colonies when individual group A or B reagents were used.
Subcutaneous phaeohyphomycosis caused by Xylohypha emmonsii
Authors: Padhye A A , Helwig W B , Warren N G , Ajello L , Chandler F W , McGinnis M R
Published: January 2020

The first human phaeohyphomycotic infection caused by Xylohypha emmonsii is described. The patient, an 83-year-old woman, developed a purpuric lesion on her left arm. The pale brown fungal elements observed in biopsy tissue consisted of thin- to thick-walled, oval to spherical, yeastlike cells with single and, occasionally, multiple buds; chains of budding cells; cells with internal septations in one and, rarely, two planes; and septate hyphae. In culture, X. emmonsii grew moderately fast at 25 degrees C, showed minimal growth at 37 degrees C, and failed to grow at 40 degrees C. It produced acropetal chains of one-celled (rarely two-celled) conidia laterally and terminally directly from vegetative hyphal cells.
Fifteen-year experience with bloodstream isolates of coagulase-negative staphylococci in neonatal intensive care
Authors: Sidebottom D G , Freeman J , Platt R , Epstein M F , Goldmann D A
Published: January 2020

Investigators worldwide, as well as the neonatologists and infection control team at our hospital, have reported that the incidence of coagulase-negative staphylococcal bacteremia in critically ill neonates has increased dramatically in recent years. To investigate these claims, we examined the results of all blood cultures obtained from 1970 to 1984 in our neonatal intensive care unit. Throughout this study period, coagulase-negative staphylococci were prominent blood culture isolates (crude overall incidence of 4.4 positive bacteremia workups per 100 neonates admitted; range, 2.5 to 6.7), representing 26.3 to 69.6% of all positive cultures. There was no significant increase in incidence over time by analysis of linear trend. Detailed analysis of data from 1976 and 1982 (two selected years for which complete information concerning culturing practices and patient characteristics was available) revealed that these observations were not explained by changes in the frequency of blood culturing. In both 1976 and 1982, the probability that a blood culture would grow coagulase-negative staphylococci increased steadily from 2 to 3% shortly after admission to reach a level of about 12% in week 3 of hospitalization, before declining to an intermediate level thereafter. This pattern is more consistent with nosocomial bacteremia than with contamination of blood cultures. Contrary to clinical reports, coagulase-negative staphylococci have been the principal pathogens isolated from blood cultures in our neonatal intensive care unit since at least 1970, with no measurable increase over the subsequent 14 years.
Controlled evaluation of blood culture medium containing gelatin and V-factor-analog for detection of septicemia in children
Authors: Stratton C W , Weinstein M P , Mirrett S , Paisley J , Lauer B A , Reller L B
Published: January 2020

Both Neisseria meningitidis and Haemophilus influenzae are important isolates recovered in blood cultures from septicemic children. Sodium polyanetholsulfonate is present in most blood culture media and can inhibit the growth of certain bacteria, including N. meningitidis. The addition of gelatin to blood culture media neutralizes this inhibition. The growth of H. influenzae is enhanced by specific growth factors such as hemin and NAD. The addition of gelatin and V-factor-analog (a proprietary supplement for enhancing the growth of H. influenzae) might have a positive effect on the yield and on the speed of detection of septicemia in children. To evaluate this possibility, we did 4,565 paired comparisons of blood cultured in BACTEC 6B (aerobic) medium with and without the addition of both 1.2% gelatin and V-factor-analog. More aerobic and facultative bacteria grew in the 6B than in the 6B-gelatin-V-factor-analog medium (P less than 0.01). Only seven isolates of Neisseria spp. were recovered during this study period, with the 6B medium performing as well as the supplemented medium. When microorganisms grew in both bottles, they did so at the same time except for H. influenzae and Candida albicans. H. influenzae was recovered earlier from the 6B-gelatin-V-factor-analog bottle (P less than 0.01), with a mean time to detection of 8.5 h compared with 15.9 h for the 6B bottle. C. albicans was recovered earlier from the 6B bottle (P less than 0.02), with a mean time to detection of 34.9 h compared with 71.6 h for the 6B-gelatin-V-factor-analog bottle. We conclude that the 6B medium in its present formulation is superior to bB supplemented with gelatin and V-factor-analog.
Proposed changes in interpretive criteria and potency of ampicillin and ampicillin-sulbactam disks for susceptibility tests
Authors: Barry A L , Jones R N
Published: January 2020

The accuracy of disk susceptibility tests with ampicillin and ampicillin-sulbactam was not improved when the amount of ampicillin was increased from 10 to 20 or 30 micrograms per disk. For testing members of the family Enterobacteriaceae, ampicillin disk tests correlated better with broth microdilution tests when the zone size standards were altered from greater than or equal to 14 greater than or equal to 17 mm for susceptible and from less than or equal to 11 to less than or equal to 13 mm for resistant. The same zone size breakpoints apply to tests with ampicillin-sulbactam disks (10/10 micrograms). When Staphylococcus, Branhamella, and Haemophilus species are tested against ampicillin, interpretive breakpoints are those separating beta-lactamase-producing strains from nonproducing strains. However, when ampicillin-sulbactam is tested, beta-lactamase enzymes are efficiently inhibited by the sulbactam component, and thus zone size standards for ampicillin do not apply: zone size standards for the Enterobacteriaceae can be used for testing the combination against Staphylococcus, Branhamella, and Haemophilus species. For Streptococcus, Enterococcus, and Listeria species, only ampicillin disks need be tested, since ampicillin-sulbactam disks give essentially identical results.
Comparative recoveries of Mycobacterium avium-M. intracellulare from isolator lysis-centrifugation and BACTEC 13A blood culture systems
Authors: Kiehn T E , Cammarata R
Published: January 2020

Blood cultures processed with a lysis-centrifugation (Isolator) system and a radiometric (BACTEC 13A) broth system were compared for the recovery of Mycobacterium avium-M. intracellulare from patients with acquired immunodeficiency syndrome. Forty-nine isolates of M. avium-M. intracellulare were recovered by both systems, 9 were recovered by the Isolator system only, and 12 were recovered by the BACTEC system only. Average times to detection were 16 and 14 days for the Isolator and BACTEC systems, respectively. There was no significant difference between the two blood culture systems in sensitivity or time to detection.
Comparison of 10 enzyme immunoassays for detection of antibody to human immunodeficiency virus type 2 in West African sera
Authors: Denis F , Leonard G , Sangare A , Gershy-Damet G , Rey J L , Soro B , Schmidt D , Mounier M , Verdier M , Baillou A
Published: January 2020

The efficacies of nine enzyme-linked immunosorbent assays (EIA) for antibody to human immunodeficiency virus type 1 (HIV-1) and one EIA for antibody to HIV-2 in detecting antibody to HIV-2 were studied. The competitive EIAs for antibody to HIV-1 were less sensitive than the indirect EIAs. The overall prevalence of positive results was between 28 and 51% with the competitive EIAs and between 70 and 93% with the indirect EIAs. Most of the EIAs were less sensitive in detecting antibody to HIV-2 in sera from people with acquired immunodeficiency syndrome-like diseases than in sera from symptomless individuals. The results indicate that there is a high degree of cross-reactivity between HIV-1 and HIV-2 by EIA, indicating that serotype specificity must be determined by Western blot (immunoblot) with both sets of viral antigens. The results are relevant for discussing public health strategies, especially the screening of blood donors; competitive EIAs for antibody to HIV-1 are not sensitive enough to be used in areas where HIV-2 is prevalent (West Africa).
Immunocytochemical detection of antibodies to Epstein-Barr virus nuclear antigen by a streptavidin-biotin-complex assay
Authors: Musiani M , Zerbini M , Plazzi M , Gentilomi G , La Placa M
Published: January 2020

An immunocytochemical staining for the detection of antibody to Epstein-Barr virus nuclear antigen in cell smears was developed by using a three-dimensional complex of streptavidin and biotin labeled with horseradish peroxidase as the detector system. The presence of antibody against Epstein-Barr virus nuclear antigen was revealed by a dark staining of the nuclei of Raji cells. A significant correlation was found between the titers obtained with our assay and titers obtained by anticomplement immunofluorescence on 110 serum samples. Our assay did not require an Epstein-Barr virus-negative serum source for fresh complement and gave a permanent record of the reaction that could easily be observed under an ordinary light microscope.
Failure of Campylobacter pylori to grow in commercial blood culture systems
Authors: Westblom T U , Madan E , Midkiff B R , Adkins V W , Subik M A
Published: January 2020

Of 50 blood culture sets, 20 Bacto (Difco Laboratories, Detroit, Mich.), 20 Septi-Chek (Hoffmann-La Roche, Inc., Nutley, N.J.), and 10 BACTEC 6B and 7D (Johnston Laboratories, Inc., Towson, Md.) sets were inoculated with Campylobacter pylori and fresh human blood. None of the 50 blood cultures produced any detectable growth. Current commercial blood culture systems may be inadequate for the detection of C. pylori bacteremia.
Alterations in the T-lymphocyte subpopulation in patients with rhinoscleroma
Authors: Berron P , Berron R , Ortiz-Ortiz L
Published: January 2020

T-lymphocyte subpopulations were studied in a group of patients with rhinoscleroma due to Klebsiella rhinoscleromatis. The data demonstrated that these patients had a significantly greater number of T-suppressor/cytotoxic lymphocytes than did clinically healthy individuals. This finding correlated with a diminished response to the T-cell mitogen concanavalin A. The evidence indicated that the T-cell response of these patients was decreased and may reflect the host's response to the bacterial invader, thus explaining the chronicity of the disease.
Mycobacterium avium complex pseudobacteriuria from a hospital water supply
Authors: Graham L , Warren N G , Tsang A Y , Dalton H P
Published: January 2020

From July 1983 through November 1985, organisms belonging to Mycobacterium avium complex were isolated from the urine of 29 patients. Strains recovered from the urine of nine patients from July 1983 through August 1984 were serotyped. Eight of the nine samples belonged to serovar 4. M. avium complex was isolated from the urine of 21 patients during the period from November 1984 through November 1985. While the possibility of a point source contamination was investigated, M. avium complex was recovered from the phenol red solution used for processing urine specimens in the mycobacteriology laboratory and the deionized tap water of that laboratory that is used to make the reagent. M. avium complex serovar 4 was subsequently recovered from the tap water of the laboratory and four hospital wards. During the year following the installation of a microbiological filter for the mycobacteriology laboratory deionized tap water, 2 urine isolates were recovered, compared to 26 the previous year. This study demonstrates the importance of filtration devices at tap water sites that are used to make laboratory reagents and the value of serotyping as a marker for the detection of a specific source of M. avium complex contamination.
Construction of a DNA probe for the specific identification of Streptococcus oralis
Authors: Schmidhuber S , Ludwig W , Schleifer K H
Published: January 2020

A DNA probe for the specific detection and identification of Streptococcus oralis was isolated from HindII-digested DNA of S. oralis NCTC 11427 and cloned in Escherichia coli. The plasmid pOS1 hybridized only to DNA of S. oralis and not to that of other viridans group streptococci.
Test-of-cure stool cultures for traveler's diarrhea
Authors: Ericsson C D , DuPont H L , Mathewson J J , Johnson P C , de la Cabada F J , Bitsura J A
Published: January 2020

Whether enteropathogens were eradicated or persisted in test-of-cure stool cultures from 251 patients with traveler's diarrhea, the durations of diarrhea were similar within the antimicrobial agent-treated (32 versus 33 h) and placebo-treated (82 versus 96 h) groups. Routine test-of-cure stool cultures can be useful for evaluating treatment failures and for assessing asymptomatic carriage of enteropathogens after treatment, but they are not mandated in the design of placebo-controlled antimicrobial treatment trials in traveler's diarrhea when the focus of the trial is clinical efficacy.
Laboratory findings in four cases of adult botulism suggest colonization of the intestinal tract
Authors: McCroskey L M , Hatheway C L
Published: January 2020

There was laboratory evidence of intestinal colonization in four cases of adult botulism confirmed by the Centers for Disease Control. No performed toxin was detected in available foods, but Clostridium botulinum was isolated from foods in two instances. Botulinal toxin was detected in the sera of all four patients, in one case at 47 days after ingestion of suspected food. C. botulinum was demonstrated in the stool of all four patients and persisted for 119 days after the onset of illness in one patient. Two patients had surgical alterations of the gastrointestinal tract, which may have promoted the colonization. The apparent lack of ingestion of performed toxin in these cases and the persistence of botulinal toxin or C. botulinum, or both, for long periods in three of the patients suggest that colonization of the intestinal tract occurred.
Staphylococcus haemolyticus urinary tract infection in a male patient
Authors: Gunn B A , Davis C E
Published: January 2020

Urinary tract infections caused by staphylococci are usually attributed to Staphylococcus epidermidis or S. saprophyticus. The case study reported here describes a persistent urinary tract infection caused by S. haemolyticus in a 38-year-old male whose infection was ultimately resolved through the use of the antibiotic trimethoprim-sulfamethoxazole.
Endocarditis caused by Capnocytophaga ochracea
Authors: Buu-Hoi A Y , Joundy S , Acar J F
Published: January 2020

Capnocytophaga ochracea is a gram-negative, fusiform bacillus which is part of the normal human oral flora. This organism is often isolated from periodontal lesions of patients with periodontitis and is associated with sepsis in granulocytopenic patients. We report here a case of endocarditis caused by C. ochracea.
Comparison of Gen-Probe commercial kit and culture technique for the diagnosis of Mycoplasma pneumoniae infection
Authors: Dular R , Kajioka R , Kasatiya S
Published: January 2020

The Gen-Probe rapid diagnostic system was compared with a culture method for the detection of Mycoplasma pneumoniae in clinical specimens. Of 116 clinical specimens, 103 (88.8%) yielded identical results. The relative sensitivity and specificity of the probe were both 89%. Rapid turnaround time and its sensitivity and specificity indicate that the probe test is a practical method for the rapid diagnosis of M. pneumoniae infections.
Homogeneous liposome lysis assay for determination of anti-streptolysin O antibody titer in serum
Authors: Umeda M , Tomita T , Shibata H , Seki M , Yasuda T
Published: January 2020

We developed a liposome lysis assay for determining anti-streptolysin O antibodies (ASO) in human sera involving the use of carboxyfluorescein-entrapped multilamellar liposomes. This assay system was based on the inhibition of streptolysin O-induced liposome lysis by ASO. Briefly, after incubation of a given amount of streptolysin O with ASO for 30 min at 37 degrees C, carboxyfluorescein-entrapped liposomes composed of egg yolk phosphatidylcholine and cholesterol in a molar ratio of 1:1 were added to the mixture to determine the residual streptolysin O activity. Liposome lysis, detected as carboxyfluorescein release from the liposomes, was inversely proportional to the ASO titer. The results of within-run and between-run precision studies indicated that the liposome lysis assay is accurate and gives reproducible data. Bilirubin, hemoglobin, and triglycerides did not interfere with the liposome lysis assay. The ASO titers of 100 patient sera, evaluated by our new method and the Rantz-Randall method, showed good correlation.