bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathogenicity of Yersinia enterocolitica serotype O3 biotype 3 strains
Authors: Kaneko S , Maruyama T
Published: January 2020

It is known that Yersinia enterocolitica infection in Japan is caused mainly by serotype O3 biotype 4 strains. Recently, however, a number of serotype O3 strains which were classified biotype 3 and which ferment lactose and xylose, instead of sorbose, and give a negative Voges-Proskauer reaction have been isolated from both humans and animals. In this study, comparisons of four properties were made among isolates of Y. enterocolitica serotype O3 biotype 3 from humans, pigs, dogs, cats, and rats and the laboratory stock strains of Y. enterocolitica biotype 4. All strains were tested for the presence of plasmids, calcium-dependent growth at 37 degrees C, autoagglutination activity at 37 degrees C, and recovery of the organisms from the stools of intravenously challenged mice. Biotypes 3 and 4 were positive for these four properties. Plasmid digestion with restriction endonucleases showed the same digestion patterns in both biotypes. These results suggest that Y. enterocolitica serotype O3 biotype 3 strains are pathogenic, as are biotype 4 strains.
Ability of ciprofloxacin but not pipemidic acid to differentiate all three biovariants of Mycobacterium fortuitum from Mycobacterium chelonae
Authors: Steele L C , Wallace R J
Published: January 2020

When tested against 312 clinical isolates of rapidly growing mycobacteria, the quinolone pipemidic acid correctly separated Mycobacterium chelonae (M. chelonei) from Mycobacterium fortuitum biovar fortuitum but not from biovar peregrinum or the third biovar complex. The new 4-quinolone ciprofloxacin correctly separated all three biovars of M. fortuitum from M. chelonae and appears to provide a better taxonomic test.
Characterization of Mycobacterium tuberculosis antigen 5 epitopes by using a panel of 19 monoclonal antibodies
Authors: Olds G R , Sanson A J , Daniel T M
Published: January 2020

Antigen 5 is a 35,000-dalton protein which has been purified from culture filtrates of Mycobacterium tuberculosis and shown by immunoprecipitation to be restricted in distribution to M. tuberculosis and M. bovis among 14 mycobacterial species studied. We raised 19 antigen 5-reactive monoclonal antibodies and used them to characterize epitopes of this antigen by enzyme-linked immunosorbent assay and immunoabsorbent affinity chromatography. Fifteen monoclonal antibodies, all immunoglobulin M (IgM), cross-reacted in two major patterns with culture filtrates from five species of mycobacteria and with purified mycobacterial arabinomannan and arabinogalactan. All 15 monoclonal antibodies also reacted with M. tuberculosis antigen 6. Immunoabsorbent affinity columns prepared with these antibodies yielded principally arabinomannan and arabinogalactan. Four monoclonal antibodies, three IgG2a and one IgM, reacted by enzyme-linked immunosorbent assay with antigens 5 and 6 exclusively and not with mycobacterial culture filtrates or polysaccharides. All four monoclonal antibodies yielded antigen 5 and small amounts of antigen 6 when used for immunoabsorbent affinity chromatography. We conclude from these studies that antigen 5 has two nonspecific epitopes, possibly carbohydrate in nature, and one apparent species-specific epitope which is shared with antigen 6.
Improved rat model for studying Pneumocystis carinii pneumonia
Authors: Bartlett M S , Queener S F , Jay M A , Durkin M M , Smith J W
Published: January 2020

Sprague-Dawley rats treated for 8 weeks with cortisone acetate (25 mg per rat twice weekly) were immunosuppressed to variable degrees. A total of 55% lost over 12% of their initial body weight, had cortisol concentrations in serum more than five times greater than those of the controls, and had markedly depressed ratios of helper to non-helper T cells, in both the spleen and peripheral blood. Animals that gained weight during immunosuppression had cortisol concentrations in serum only three times higher than those of the controls, had normal ratios of helper to non-helper T cells in the spleen, and had only modestly reduced T-cell ratios in peripheral blood. The degree of Pneumocystis pneumonia was evaluated in impression smears and sections of lungs taken from immunosuppressed rats. Pneumocystis infections were more severe in the rats that showed the greatest weight loss. Weight change during immunosuppression may therefore be used as a reliable means for predicting the degree of Pneumocystis infection in living rats. This protocol allows the selection of uniformly infected rats for studies assessing drug therapy of Pneumocystis pneumonia.
Ewingella americana: recurrent pseudobacteremia from a persistent environmental reservoir
Authors: McNeil M M , Davis B J , Solomon S L , Anderson R L , Shulman S T , Gardner S , Kabat K , Martone W J
Published: January 2020

From September 1981 through April 1984, 20 patients at one hospital were identified with Ewingella americana pseudobacteremia. Case-control studies demonstrated an association between having a positive blood culture for E. americana and having blood for culture obtained simultaneously with blood obtained for coagulation studies (15 of 19 case patients versus 4 of 38 controls; P = 4.5 X 10(-7)). Review of blood-drawing procedures showed that blood for coagulation studies and culture was drawn with the same syringe, and coagulation tubes were filled before blood culture tubes. Some phlebotomists were not using new sterile needles to inoculate blood culture bottles. Collection tubes for coagulation studies were prepared in the hospital, and E. americana was isolated from all 52 unused coagulation tubes tested. Solutions prepared in the hospital may constitute a persistent inanimate environmental reservoir for this uncommon microorganism. Pseudobacteremia can result in unnecessary antimicrobial therapy for some patients, incurring the risks of adverse drug reactions, selection of drug-resistant bacteria, and increased health care costs.
Plasmids of Ewingella americana: supplementary epidemiologic markers in an outbreak of pseudobacteremia
Authors: Clark N , McNeil M M , Swenson J M , O'Hara C , Riddle C F , Anderson R L , Davis B J , Shulman S T , Martone W J , Solomon S L
Published: January 2020

During an outbreak of pseudobacteremia in a children's hospital, Ewingella americana was found in blood cultures from 20 patients. E. americana was inoculated into blood culture bottles at the time of specimen collection due to cross contamination from nonsterile, citrated blood collection tubes used for coagulation studies. Antimicrobial susceptibility testing and plasmid profiling were used to assess the association between patient isolates and isolates from unused blood collection tubes. All E. americana isolates had similar antibiograms (i.e., resistance only to cephalothin) when tested at 37 degrees C. However, when the same isolates were tested for antimicrobial susceptibility at 25 degrees C, a different antibiogram (i.e., resistance to chloramphenicol, ampicillin, and cephalothin) was found. The majority of these isolates also demonstrated a unique four-plasmid profile (130, 56, 4.6, and 3.1 megadaltons), and two of these plasmids (130 and 56 megadaltons) were characterized as temperature-sensitive plasmids. An epidemiologic link between outbreak-associated isolates obtained from different time periods in the outbreak was supported by evidence of a significant trend in the ability of the outbreak-associated isolates to reduce nitrate, together with the presence of the resistance antibiogram at 25 degrees C and the demonstration of the unique four-plasmid profile.
Production and characterization of monoclonal antibodies to toxic shock syndrome toxin 1 and use of a monoclonal antibody in a rapid, one-step enzyme-linked immunosorbent assay for detection of picogram quantities of toxic shock syndrome toxin 1
Authors: Wells D E , Reeves M W , McKinney R M , Graves L M , Olsvik O , Bergan T , Feeley J C
Published: January 2020

Twenty-six hybridoma cell lines that produced monoclonal antibodies to toxic shock syndrome toxin 1 (TSST-1) were generated by immunizing mice with a highly purified preparation of TSST-1 and fusing their splenic lymphocytes with SP2/0-Ag-14 cells. One monoclonal antibody of the immunoglobulin G1 isotype, designated as PEC-1 10-2SCH, was selected for extensive study. The specificity of this antibody was determined by testing spent culture fluid filtrates of TSST-1- and non-TSST-1-producing strains of Staphylococcus aureus by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and enzyme-linked immunoelectrotransfer blot techniques. Monoclonal antibody PEC-1-10-2SCH was specific for TSST-1-producing strains of S. aureus, reacting with TSST-1 and two other proteins which appear to be unique to S. aureus strains that produce TSST-1. Monoclonal antibody PEC-1-10-2SCH was used in conjunction with polyclonal rabbit antibodies to TSST-1 in a rapid, one-step, sensitive, specific, and quantitative enzyme-linked immunosorbent assay. This assay was shown to be more sensitive, faster, and simpler to perform than previously described isoelectric focusing, immunodiffusion, and solid-phase radioimmunoassays for TSST-1. Monoclonal antibody PEC-1-10-2SCH was not reactive with Staphylococcus protein A under the conditions of the test.
Duration of tick attachment and Borrelia burgdorferi transmission
Authors: Piesman J , Mather T N , Sinsky R J , Spielman A
Published: January 2020

Nymphal Ixodes dammini transmitted Borrelia burgdorferi to 1 of 14 rodents exposed for 24 h, 5 of 14 rodents exposed for 48 h, and 13 of 14 rodents exposed for greater than or equal to 72 h. Prompt removal of attached ticks is a prudent public health measure, especially in regions where Lyme disease is endemic.
Bordetella bronchiseptica bronchitis
Authors: Papasian C J , Downs N J , Talley R L , Romberger D J , Hodges G R
Published: January 2020

The clinical course of a patient with bronchitis caused by Bordetella bronchiseptica is described. The organism was recovered on one occasion from a protected catheter brush specimen obtained at bronchoscopy and on two occasions from expectorated sputum specimens. The infection was eradicated with antimicrobial therapy.
Increased microbial yield from continuous ambulatory peritoneal dialysis peritonitis effluent after chemical or physical disruption of phagocytes
Authors: Taylor P C , Poole-Warren L A , Grundy R E
Published: January 2020

The laboratory diagnosis of continuous ambulatory peritoneal dialysis-associated peritonitis is often hindered by either the absence of or the recovery of low numbers of viable microorganisms. This may be the result of sequestration of bacteria within phagocytes. Sonication of clinical specimens prior to culturing or culturing on saponin-containing media resulted in the growth of significantly greater numbers of colonies than standard culturing on conventional media. In addition, the demonstration that microorganisms are sequestered in phagocytes helped to establish the pathogenic nature of such isolates and distinguish them from contaminants even when present in low numbers. A variety of physical and chemical techniques can disrupt phagocytes and improve the sensitivity of laboratory methods used to confirm the diagnosis of peritonitis in continuous ambulatory peritoneal dialysis patients.
Rapid automated method for screening of enteric pathogens from stool specimens
Authors: Villasante P A , Agulla A , Merino F J , Pérez T , Ladrón de Guevara C , Velasco A C
Published: January 2020

A total of 800 colonies suggestive of Salmonella, Shigella, or Yersinia species isolated on stool differential agar media were inoculated onto both conventional biochemical test media (triple sugar iron agar, urea agar, and phenylalanine agar) and Entero Pathogen Screen cards of the AutoMicrobic system (Vitek Systems, Inc., Hazelwood, Mo.). Based on the conventional tests, the AutoMicrobic system method yielded the following results: 587 true-negatives, 185 true-positives, 2 false-negatives, and 26 false-positives (sensitivity, 99%; specificity, 96%). Both true-positive and true-negative results were achieved considerably earlier than false results (P less than 0.001). The Entero Pathogen Screen card method is a fast, easy, and sensitive method for screening for Salmonella, Shigella, or Yersinia species. The impossibility of screening for oxidase-positive pathogens is a minor disadvantage of this method.
Phaeohyphomycotic cyst caused by a recently described species, Phaeoannellomyces elegans
Authors: Engleberg N C , Johnson J , Bluestein J , Madden K , Rinaldi M G
Published: January 2020

An 81-year-old man presented with a chronic, painful nodule on the palmar surface of the left fourth finger. As a former farm worker, the patient acknowledged frequent soil-contaminated wounds of the left hand 4 to 12 years previously, but he denied any recent trauma. The patient's other medical problems included a history of chronic immunoglobulin A gammopathy and a new pleural mass eroding into adjacent ribs on chest X-ray. The finger nodule was excised and consisted of an intact phaeohyphomycotic cyst which yielded growth of a darkly pigmented fungus. At 25 degrees C, the isolate formed annellidic yeast cells having dark-brown walls consistent with the recently described species Phaeoannellomyces elegans. In vitro antifungal susceptibility tests indicated resistance to amphotericin B and variable susceptibility to imidazoles. The lesion was excised, and the patient received no antifungal therapy. After 9 months of follow-up, the fungal infection shows no signs of recurrence.
Detection of hemagglutinins in cultures of squirrel monkey intestinal trichomonads
Authors: Pindak F F , Gardner W A , Mora de Pindak M , Abee C R
Published: January 2020

Intestinal trichomonads are very common inhabitants of captive squirrel monkeys. In evaluating the potential pathogenicity of these organisms, we encountered hitherto unknown hemagglutinins in their culture fluids. The cytopathic effect associated with a number of the isolates resembled that caused by vacuolating viruses. We have ruled out conventional viruses as the cause of the cytopathic effect and as the source of the hemagglutinin. The agglutinin has some of the basic characteristics of lectins. Parallel experiments demonstrated agglutination of erythrocytes from squirrel monkeys, humans, dogs, cats, guinea pigs, and horses, with the first two types being the most sensitive. Relatively less agglutination was seen with rat erythrocytes. Agglutination of sheep, rabbit, chicken, and bovine erythrocytes was virtually absent.
Evaluation of YeastIdent and Uni-Yeast-Tek yeast identification systems
Authors: Salkin I F , Land G A , Hurd N J , Goldson P R , McGinnis M R
Published: January 2020

The accuracy of the new API YeastIdent system and the Flow Laboratories Uni-Yeast-Tek identification kit with an expanded data base was evaluated in comparison to the API 20C yeast identification system by three laboratories. A total of 489 test isolates were used, biased toward yeasts commonly encountered in clinical specimens. Isolates not in a system's data base were not counted in the evaluation of that system. For isolates in their data base, YeastIdent was 55% accurate and Uni-Yeast-Tek was 40% accurate. By the manufacturer's criteria of reliable identification without additional tests, both systems failed to identify many common and uncommon species. The limited number of substrates and difficulties in assessing results obtained with 11 of the API YeastIdent substrates and apparent errors in the expanded Uni-Yeast-Tek data base appeared to be major factors limiting the accuracy of these systems.
Detection of antibodies to Anaplasma marginale by an improved enzyme-linked immunosorbent assay with sodium dodecyl sulfate-disrupted antigen
Authors: Winkler G C , Brown G M , Lutz H
Published: January 2020

Sensitivities of two enzyme-linked immunosorbent assays (ELISAs) with particulate and sodium dodecyl sulfate (SDS)-disrupted Anaplasma marginale antigen were compared. The quotient of positive reference sera divided by the absorbance quotient of a negative reference serum at identical dilution was termed the signal-to-noise ratio. Optimal signal-to-noise ratios were dependent on both pretreatment of antigen and antigen concentration. SDS disruption of anaplasmal antigen resulted in a markedly improved signal-to-noise ratio of ELISA compared with ELISA with untreated antigen at identical antigen and serum dilutions. This represented higher sensitivity and lower background absorbance of the ELISA with disrupted antigen. SDS-disrupted A. marginale antigen was standardized by protein determination, and antigen, as well as precoated microtiter wells, was stored frozen without apparent loss of antigenic properties. ELISA results were in agreement with results of positive and negative control sera tested by the complement fixation test or by light microscopy Anaplasma diagnosis in Giemsa-stained blood films.
Influence of growth medium and supplement on growth of Haemophilus influenzae and on antibacterial activity of several antibiotics
Authors: Bergeron M G , Simard P , Provencher P
Published: January 2020

In the present study, five non-beta-lactamase- and five beta-lactamase-producing strains of Haemophilus influenzae were used to determine whether three different growth media, Mueller-Hinton broth and agar, brain heart infusion broth and agar, and tryptic soy broth and agar, and their added supplements (0.2% hemin-0.1% IsoVitaleX, 1% hemin-1% IsoVitaleX, 2% sheep blood, 10% Fildes enrichment, 5% Fildes enrichment, 1% supplement B, 5% horse erythrocytes, and 2% hemoglobin-1% IsoVitaleX) would influence the growth rate of this microorganism and the antibacterial activity of eight antibiotics, including ampicillin, tetracycline, chloramphenicol, gentamicin, cefamandole, erythromycin, trimethoprim-sulfamethoxazole (TMP-SMX), and cefoperazone. The growth curve studies were carried out with an initial inoculum of 10(4) bacteria per ml, and MICs were determined with an inoculum of 5 X 10(5) microorganisms. Mueller-Hinton broth, brain heart infusion broth, and tryptic soy broth enriched with 5% Fildes resulted in a maximal growth of more than 10(8) CFU/ml at 24 h. When 10% Fildes or 2% sheep blood was added as enrichment to Mueller-Hinton broth, a considerable reduction in the growth rate of H. influenzae strains resulted (P less than 0.01). Significant variations in MICs (P less than 0.01) were observed with chloramphenicol, TMP-SMX, erythromycin, and cefoperazone when brain heart infusion agar, Mueller-Hinton agar, or tryptic soy agar was used. Chloramphenicol, gentamicin, erythromycin, and TMP-SMX were all affected by the different enrichments added to Mueller-Hinton agar. MICs were in general higher with 5% Fildes enrichment and lower with 1% supplement B. Cefoperazone was the only drug which exhibited a lower MIC in 5% Fildes enrichment for ampicillin-resistant H. influenzae strains.
Numerical analysis of electrophoretic protein patterns of Bacteroides ureolyticus clinical isolates
Authors: Taylor A J , Costas M , Owen R J
Published: January 2020

A total of 37 Bacteroides ureolyticus clinical isolates (mainly from the United Kingdom) comprising 18 nongonococcal urethritis-associated strains and 19 other strains, including the type strain (NCTC 10941T) and strains from abscesses, ulcers, and various other soft tissue lesions, and five reference strains of other Bacteroides, Fusobacterium, Megamonas, and Sebaldella species were characterized by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cellular proteins. The protein patterns, which contained 45 to 50 discrete bands, were highly reproducible and were used as the basis for a numerical analysis. Four clusters comprising 31 strains of B. ureolyticus were obtained at the 70% similarity level, and one of these was further divided to give two subclusters at the 82% similarity level. The analysis showed that the clusters obtained corresponded with three previously identified polyacrylamide gel electrophoresis types (I, II, and III) within the species, although two slightly different patterns within type I were detected. Evidence is presented for a new protein pattern (type IV) which was characteristic of NCTC 10941T and seven isolates. There was no clear-cut correlation between the pattern type and the clinical source of the isolates, except for the type Ib and type IV strains, which were nongonococcal urethritis-associated and wound isolates, respectively.
Development of an immunoglobulin A-specific anti-Haemophilus influenzae antibody assay for detection of antibody in human mucosal secretions
Authors: Yeung S , Pang G , Cripps A W , Clancy R L
Published: January 2020

A micro-enzyme-linked immunosorbent assay for quantitation of immunoglobulin A-specific anti-Haemophilus influenzae antibody is described and characterized. It had a sensitivity of 27 ng/ml, which is appropriate to detect antibody levels in normal saliva. Specificity for H. influenzae was achieved with the H1H2 group of antigens. Absorption studies for a range of bacteria showed little cross-reactivity, with the exception of Pseudomonas aeruginosa. Absorption studies involving various antigen preparations obtained from H. influenzae indicated that the H1H2 antigen group included significant amounts of surface antigen. An analysis of saliva from normal subjects and patients with chronic obstructive lung disease showed significant differences in levels of antibody, highlighting the potential value of the assay.
Application of DNA typing methods to epidemiology and taxonomy of Candida species
Authors: Scherer S , Stevens D A
Published: January 2020

Methods are described for extraction of DNA from the yeast form of Candida spp., followed by digestion and electrophoresis of DNA fragments. The resulting gel patterns (greater than 100 bands) were used to type Candida isolates. Four intense bands identified, three of which are present in each isolate (6 to 7, 3.7 or 4.2, and 2.5 to 3 kilobases), appear to be DNA encoding the rRNA. The methods proved to be both simple and reproducible. The patterns were shown to be stable through several hundred doublings from multiple single colonies. A survey of isolates showed that, on the basis of similarity of gel patterns, several Candida species could be sorted into mutually exclusive groups, and subgroups could be created. Analyses of this survey suggested the possible epidemiologic and taxonomic applications of these methods. DNA typing methods appear to offer important potential advantages over phenotyping methods. The methods provide a base for further epidemiologic studies and for further development of techniques, such as the use of cloned probes for studies of DNA homology.
High levels of antibodies to streptococcal cell membrane antigens specifically bound to monoclonal antibodies in acute poststreptococcal glomerulonephritis
Authors: Yoshimoto M , Hosoi S , Fujisawa S , Sudo M , Okuda R
Published: January 2020

We produced 15 immunoglobulin G class monoclonal antibodies against antigens of the streptococcal cell membrane (SCM) of Streptococcus pyogenes (T type 12, Tanaka strain) and determined the levels in human sera of antibodies against Triton-X-extracted antigens specifically bound to each of these 15 monoclonal antibodies by enzyme-linked immunosorbent assay. Sample sera were obtained from 10 normal controls (group 1), 10 patients with streptococcal pharyngitis without sequelae (group 2), and 8 patients with acute poststreptococcal glomerulonephritis (APSGN) (group 3). Anti-streptolysin O (ASO) titers of the sera increased in the order of groups 1, 2, and 3. There was no relationship between ASO titer and the level of anti-SCM antibodies, and there was no significant difference in the level of anti-SCM antibodies determined with each of the 15 monoclonal antibodies between group 1 and group 2 sera. Group 3 sera had higher levels of antibodies to SCM antigens specifically bound to each of 14 of these 15 monoclonal antibodies than group 1 or group 2 sera did. Of these 14 monoclonal antibodies, 9 reacted with the four SCM antigens separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrophoretically transferred to a nitrocellulose sheet. These results suggest that high levels of antibodies to SCM antigens are related to the development of APSGN and that the systemic immune response to SCM antigens is involved in the pathogenesis of APSGN.
Campylobacter hyointestinalis associated with human gastrointestinal disease in the United States
Authors: Edmonds P , Patton C M , Griffin P M , Barrett T J , Schmid G P , Baker C N , Lambert M A , Brenner D J
Published: January 2020

Campylobacter hyointestinalis was isolated from stool specimens of four persons, all of whom were experiencing nonbloody, watery diarrhea. The youngest (8 months of age) and the oldest (79 years of age) individuals were females, and the other two were homosexual men. C. hyointestinalis was the only clinically significant pathogen isolated from stool specimens for three of the individuals. In case 3 (involving a 37-year-old homosexual man), Entamoeba histolytica and Shigella sonnei were also present in the stool. The identification of all C. hyointestinalis strains was made biochemically and confirmed by DNA hybridization. This study documented the isolation of C. hyointestinalis from four patients with diarrhea, and our findings suggest that the clinical significance of Campylobacter species must be expanded to include C. hyointestinalis as a potential cause of human gastrointestinal disease.
Evaluation of immuno-dot-blot assay for detection of cholera-related enterotoxin antigen in Salmonella typhimurium
Authors: Panigrahi D , Burks M , Hariharan H , Finkelstein R A
Published: January 2020

Twenty-five strains of Salmonella typhimurium isolated in India were examined for the presence of cholera/coli-related enterotoxin antigen by a previously described latex particle agglutination test and by a newly developed immuno-dot-blot test using immunopurified goat antibody against the cholera-related enterotoxin isolated from an Escherichia coli strain of human origin. The immuno-dot-blot assay could detect 0.02 ng of purified enterotoxin. The amount of toxin antigen detected varied widely from strain to strain. Fourteen of the 25 polymyxin B-treated extracts of bacteria harvested from 6-h Casamino Acids-yeast extract broth cultures gave positive results in both serologic assays as well as in rabbit skin tests for delayed permeability factor. An additional strain was positive only in the immuno-dot-blot. Five of six stool isolates and six of seven blood isolates tested gave positive reactions. Two isolates of Salmonella enteritidis tested were also positive. The immuno-dot-blot test appears to be a simple, rapid, and reliable method for detection of cholera-related enterotoxin antigen in S. typhimurium. The demonstration of a cholera-related enterotoxin, even in small amounts, in a facultative intracellular pathogen raises interesting questions regarding its potential role in pathogenesis both of diarrheal disease and systemic infections caused by salmonellae.
Density profile of group B streptococci, type III, and its possible relation to enhanced virulence
Authors: Håkansson S , Holm S E , Wagner M
Published: January 2020

The buoyant densities of virulent and colonizing group B streptococci, type III, were determined by centrifugation of bacteria on a linear, hypotonic density gradient. A total of 28 strains were investigated. Eleven strains were obtained from blood cultures of babies with early-onset disease, and eight strains were isolated from the cerebrospinal fluid of babies with late-onset septicemia and meningitis. Nine colonizing strains were genital isolates from pregnant women subsequently giving birth to healthy children. In each strain the buoyant density was determined before and after neuraminidase treatment. All strains showed an increase in the buoyant density after enzymatic removal of sialic acid, and the density differences before and after desialylation were calculated. The mean values of these differences for blood, cerebrospinal fluid, and colonizing isolates were 23.4, 25.3, and 10.6 mg/ml, respectively. The mean value for the colonizing strains differed significantly from the mean value for each group of virulent strains. All colonizing strains banded singly in the gradient, whereas five of the virulent strains divided into two density populations. Extracts of the low-density cells produced markedly more dense immunoprecipitates with type antiserum than did extracts of the high-density bacteria. One double-banding strain was positive for R protein. After separation of the two density populations, this antigen was detected only in the low-density population. The results indicate that bacterial buoyant density is inversely related to the amount of capsular polysaccharide enveloping the cell and that a determination of the density profile of the bacteria may be used for discriminating strains with an increased pathogenic potential.
Comparison of blood culture methods for recovery of Legionella pneumophila from the blood of guinea pigs with experimental infection
Authors: Reinhardt J F , Nakahama C , Edelstein P H
Published: January 2020

Blood was cultured from guinea pigs with experimental Legionella pneumophila serogroup 1 pneumonia, using four different methods. A 0.03-ml amount was spread onto each of several plates of buffered charcoal-yeast extract supplemented with alpha-ketoglutarate (BCYE) (direct plate); 1.5 ml each was inoculated into a BCYE agar-yeast extract broth bottle (biphasic), a pediatric Isolator tube (E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.), and a glass tube containing 0.025% sodium polyanethanolsulfonate. Blood processed in the Isolator tube was plated on BCYE, as was the buffy coat blood fraction, which was obtained by centrifugation of the tube containing sodium polyanethanolsulfonate and blood. Observations were made of the number of positive cultures, the time to detection of positive cultures, and the absolute bacterial concentrations. Each system was equally sensitive in detecting bacteremia. The biphasic method required 5 days for cultures to become positive, whereas the other systems required 2 to 3 days to detect all positive cultures (P = 1.3 X 10(-5) by Friedman group statistic, and P less than 10(-5) for comparison of the biphasic and other methods). The direct plating method demonstrated the best quantitative recovery of L. pneumophila in comparison to the other methods tested (P = 2.0 X 10(-5) by analysis of variance group statistic and P less than 0.05 for comparison between each of the methods). Quantitative recovery by the Isolator method was intermediate between the direct plating and buffy coat methods. The biphasic and Isolator blood culture methods performed poorly in comparison to the other methods, indicating the need for caution in choosing blood culture methods for Legionella isolation.
Attempted reduction of Abbott MS-2 false-susceptible errors for cefotaxime-resistant Pseudomonas aeruginosa by medium modification
Authors: Lander D W , Jungkind D L , Stone L L
Published: January 2020

Thirty-five modifications of Abbott MS-2 growth medium were evaluated in an attempt to reduce the high frequency of false-susceptible errors produced by the MS-2 system when testing resistant Pseudomonas aeruginosa against cefotaxime. A hypotonic modification with 0.1% KNO3 reduced the errors from 41 to 20% for 23 resistant isolates. All hypertonic modifications proved unsatisfactory. No modification reduced false-susceptible errors to acceptable clinical levels.
Nutritionally variant Streptococcus pyogenes from a periorbital abscess
Authors: Kocka F E , Chittom A L , Sanders L , Hernandez L , Soriano E , Jacobs N , Carey R B
Published: January 2020

A nutritionally variant Streptococcus pyogenes strain was isolated from a periorbital abscess. The organism was identified with the use of three rapid biochemical test kits, and the group A antigen was detected by conventional serology as well as direct antigen detection tests.
Quantitative epifluorescence assay of adherence of coagulase-negative staphylococci
Authors: Dunne W M , Sheth N K , Franson T R
Published: January 2020

A quantitative epifluorescence assay was developed to assess the adherent qualities of clinical isolates of coagulase-negative staphylococci. This method compared favorably with the standardized tube adherence assay, yet demonstrated a wide range of surface binding affinities among the slime-producing and non-slime-producing strains of coagulase-negative staphylococci examined. This technique can also be adapted to evaluate the adherence of bacteria to other plastics and biomedical materials used to manufacture implantable medical devices.
Pseudomonas sp. group Ve-2 bacterial peritonitis in a patient on continuous ambulatory peritoneal dialysis
Authors: Amber I J , Reimer L G
Published: January 2020

Pseudomonas sp. group Ve-2 peritonitis occurred in a patient on continuous ambulatory peritoneal dialysis who had recently completed intraperitoneal cephalosporin therapy for culture-negative peritonitis. This is the second reported case of peritonitis in this population of patients due to this unusual organism, which is usually resistant to most cephalosporin antibiotics.
Application of whole-cell DNA restriction endonuclease profiles to the epidemiology of Clostridium difficile-induced diarrhea
Authors: Kuijper E J , Oudbier J H , Stuifbergen W N , Jansz A , Zanen H C
Published: January 2020

Two patients in one hospital room acquired pseudomembranous colitis, one shortly after the other. The DNA restriction patterns of isolates from the patients and of four isolates from the environment were indistinguishable from one another and differed from isolates of other patients. Restriction endonuclease digest analysis appears to be a useful method for studying the epidemiology of Clostridium difficile.
Comparison of nasopharyngeal aspirate and nasopharyngeal swab specimens for respiratory syncytial virus diagnosis by cell culture, indirect immunofluorescence assay, and enzyme-linked immunosorbent assay
Authors: Ahluwalia G , Embree J , McNicol P , Law B , Hammond G W
Published: January 2020

Paired nasopharyngeal aspirate (NPA) and nasopharyngeal swab (NPS) specimens obtained from each of 32 hospitalized infants with X-ray-confirmed pneumonia (91%) or bronchiolitis were tested for respiratory syncytial virus (RSV) infection by virus culture, the indirect immunofluorescent-antibody (IFA) technique, enzyme-linked immunosorbent assay (ELISA; Ortho Diagnostic Systems, Inc.), and spot hybridization with a human genomic probe to quantitate cellular DNA. RSV was isolated in cell cultures from 72% (23 of 32) of patients by using NPA specimens compared with 47% (15 of 32) by using NPS specimens. With tissue culture positivity as the reference test, the sensitivities of the ELISA on NPA and NPS specimens were found to be 69% (16 of 23) and 61% (14 of 23), respectively, with a specificity and a positive predictive value from both sites of 100%. The sensitivities of the IFA technique compared with the cell culture on NPA and NPS specimens were 61% (14 of 23) and 52% (12 of 23) with specificities of 89 and 78% and positive predictive values of 96 and 92%, respectively. Despite the recovery of significantly more cells (as shown by detection of more cellular DNA by using NPA specimens), virus was detected by the IFA technique or ELISA at similar frequencies in paired specimens. However, virus was recovered more often from NPA than NPS specimens by cell culture, and ELISA optical density readings and the number of RSV-positive fluorescing cells were greater for NPA specimens. NPA specimen collection was less traumatic for the patient, was an easier procedure for the physician to perform, and provided a superior laboratory specimen for RSV diagnosis than the NPS technique.
Failure of immunosuppressive mechanisms in human Schistosoma mansoni infection with hepatosplenomegaly
Authors: Tweardy D J , Osman G S , el Kholy A , Ellner J J
Published: January 2020

The basis for development of hepatosplenic disease and attendant morbidity in Schistosoma mansoni-infected individuals is uncertain but may relate to defective modulation of immunopathology. Individuals 14 to 30 years of age from a village in the Nile Delta in Egypt were selected for study: 32 were infected with S. mansoni but lacked hepatosplenomegaly (mean fecal egg excretion +/- standard error of the mean, 1,142 +/- 79 eggs per g), 9 had S. mansoni infection and hepatosplenomegaly (1,267 +/- 197 eggs per g), and 12 were uninfected. The ratio of OKT4 helper/OKT8 suppressor cells in peripheral blood mononuclear cells was reduced in infected subjects without hepatosplenomegaly to 1.4 +/- 0.1 compared with a ratio of 1.7 +/- 0.1 (P less than 0.05) in uninfected subjects. In contrast, this ratio was increased in the group with hepatosplenomegaly to 2.7 +/- 0.3 (P less than 0.01). Schistosome antigen-induced [3H]thymidine incorporation in peripheral blood mononuclear cells was comparable in infected subjects without (5,837 +/- 1,009 cpm) and with (3,329 +/- 738 cpm; P greater than 0.1) hepatosplenomegaly. Depletion of adherent suppressor cells significantly increased the responses in the group lacking organomegaly (14,028 +/- 1,683 cpm; P less than 0.001) but not in the hepatosplenomegaly group (5,046 +/- 1,830 cpm; P greater than 0.5); this difference in response of nonadherent cells to soluble worm antigenic preparation was statistically significant (P less than 0.02) and not explained by quantitative shifts in OKT8 suppressor cells. Thus, in S. mansoni infection, subjects with hepatosplenomegaly are distinctive in their lack of an immunosuppressive balance of T-lymphocyte subpopulations and in the absence of functional adherent suppressor cells. Defective immunoregulatory mechanisms could be important in the genesis of hepatosplenic disease and its morbid sequelae.
New method of serotyping Escherichia coli: mathematical development
Authors: Thompson C J
Published: January 2020

A mathematical analysis of serological data has provided the basis for a new serotyping routine. This paper describes the process whereby the results of agglutination reactions between the standard O antigens of Escherichia coli and rabbit antisera raised against them were used to produce a much simpler, faster, and cheaper method of serotyping. This new method for serotyping E. coli requires on average only one-fifth of the serum used in the previous method and requires less than half the laboratory time. By using this method, an efficient serotyping routine can be established for any set of comparable data regardless of the bacterial group.
Comparison of genomic, plasmid, synthetic, and combined DNA probes for detecting Plasmodium falciparum DNA
Authors: McLaughlin G L , Collins W E , Campbell G H
Published: January 2020

Total genomic Plasmodium falciparum DNA, the plasmid clone pRepHind, and a 21-base-long synthetic DNA probe (PFR1), the sequence of which was derived from pRepHind, were hybridized with DNA from various species of the phylum Apicomplexa. The genomic probe hybridized with P. reichenowi and P. falciparum DNA and significantly cross-hybridized with DNA of all the other Plasmodium species tested. The synthetic and plasmid probes hybridized to P. falciparum DNA and at reduced levels to P. reichenowi but did not hybridize to P. vivax, P. malariae, P. ovale, P. fragile, P. inui, P. knowlesi, Babesia bovis, B. microti, B. bigemina, Anopheles sp., Pan sp., Aotus sp., or human DNA. Southern blot analysis indicated that approximately 60 distinct restriction enzyme fragments from P. falciparum DNA were similarly detected by PFR1 and pRepHind. A method was developed by using a second brief hybridization with synthetic DNA to amplify signals from samples that were previously hybridized with plasmid-borne repetitive DNA. This amplification procedure was shown to allow the detection of 0.005% P. falciparum parasitemias from 10-microliter samples of blood from patients in Kenya.
Crohn's disease-isolated mycobacteria are identical to Mycobacterium paratuberculosis, as determined by DNA probes that distinguish between mycobacterial species
Authors: McFadden J J , Butcher P D , Chiodini R , Hermon-Taylor J
Published: January 2020

DNA extracted from an unclassified Crohn's disease-isolated Mycobacterium strain was cloned. The recombinant clones were radiolabeled and hybridized to restriction digests of mycobacterial DNA transferred to nylon membranes. Restriction fragment length polymorphisms (RFLPs) were identified that distinguished between mycobacterial DNA samples. Quantitative estimates of frequencies of DNA base substitution were also obtained. No RFLPs were detected between the DNA of three unclassified Crohn's disease-isolated mycobacteria and Mycobacterium paratuberculosis, although several RFLPs were detected that distinguished between M. paratuberculosis and both M. avium complex serovars 2 and 5. The frequency of DNA base substitution between M. paratuberculosis and M. avium complex serovar 2 was measured as 0.87 (+/- 1.2)%.
Comparison of the Chinese schema and the International Antigenic Typing System for serotyping Pseudomonas aeruginosa
Authors: Liu P V
Published: January 2020

Twelve strains of Pseudomonas aeruginosa representing 12 serogroups in the serogrouping schema used in the People's Republic of China were compared with serogroups in the International Antigenic Typing System (IATS). The first eight groups originated in the People's Republic of China, and group II appears to have a new major antigen that is not found in the IATS. Groups I, III, IV, V, VI, VII, and VIII correspond to groups 11, 6, 9, 4, 8, 3, and 1, respectively, of the IATS. Groups IX, X, XI, and XII are immunotypes 3, 4, 5, and 1, respectively, of Fisher et al. (M. W. Fisher, H. B. Devlin, and F. J. Gnabasik, J. Bacteriol., 98:835-836, 1969); they exhibited a wide range of serological cross-reactions but correspond mainly to IATS groups 2, 3, 10, and 6, respectively.
Detection of feline leukemia virus infection in saliva
Authors: Lutz H , Jarrett O
Published: January 2020

The question was investigated whether feline leukemia virus (FeLV) infection may be diagnosed by testing saliva in an enzyme-linked immunosorbent assay (ELISA). Saliva was collected with commercially available swabs, eluted from the swabs, and tested in the ELISA. A comparison of results with saliva and serum samples from 60 specific-pathogen-free cats, 9 experimentally infected cats, and 1,117 field cats led to the following conclusions. False-positive saliva results, if any occurred, were rare events. During experimental infections, antigen excretion in saliva was observed 1.5 weeks after the first appearance of FeLV antigen in serum. In one of four positive serum samples from sick animals brought to veterinarians, saliva samples tested negative. The use of saliva in an ELISA for the detection of FeLV p27 in individual sick cats is therefore less reliable than the use of serum. In seven cats with diseases typical of FeLV, including one with an intestinal form of lyphosarcoma, saliva tested positive and serum tested negative. Based on the saliva and serum results for cats living in 92 multicat households, it was concluded that saliva may be a useful secretion for FeLV screening.
Diagnostic efficacy of two rapid tests for detection of respiratory syncytial virus antigen
Authors: Kumar M L , Super D M , Lembo R M , Thomas F C , Prokay S L
Published: January 2020

With the availability of ribavirin therapy for serious respiratory syncytial virus (RSV) infections, rapid diagnostic tests for the detection of RSV antigen are increasingly important. Efficacies of a commercially available enzyme immunoassay (EIA) (Abbott Laboratories, North Chicago, Ill.) and a fluorescent-antibody assay (FA) were evaluated in a study involving 135 specimens from children with respiratory symptoms. A nasal wash specimen was cultured immediately on RSV-sensitive A549 cells; the nasal wash was also used for EIA. FA was performed on a nasopharyngeal swab specimen with bovine anti-RSV and anti-bovine immunoglobulin G antisera (Burroughs Wellcome Co., Research Triangle Park, N.C.). A total of 39 specimens (28%) were tissue culture positive, including 35 EIA-positive and 37 FA-positive samples (sensitivities, 90 and 95%, respectively). All 96 tissue culture-negative specimens were EIA negative (specificity, 100%); 94 of these 96 specimens were FA negative (specificity, 98%). Positive and negative predictive values for the tests were as follows: 100 and 96% for EIA, respectively, and 95 and 98% for FA, respectively. Other viruses, including influenza A virus, adenovirus, enterovirus, and herpes simplex virus, were isolated in nine cases. One adenovirus-positive specimen had a false-positive RSV FA result; all nine specimens were RSV EIA negative. Both tests performed well in our study and provide cost-effective alternatives to tissue culture. The RSV EIA, in particular, uses standard serologic techniques and equipment and does not require expertise in virology. More widespread availability of rapid diagnostic tests for RSV will hopefully result in early and appropriate use of antiviral therapy in patients at risk for serious RSV infections.
Congo red uptake by motile Aeromonas species
Authors: Statner B , George W L
Published: January 2020

Virulence of several species of enteropathogenic bacteria has been correlated with the ability of isolates to take up the dye Congo red. To determine whether Congo red uptake might be a useful marker for virulence of motile Aeromonas species, we examined 50 strains of diverse clinical origin on a medium containing 50 micrograms of Congo red per ml. All of the strains took up the dye to various degrees. For most strains, uptake was greatest at 37 degrees C and least at 22 degrees C. Production of acetyl methyl carbinol (Voges-Proskauer test) or lysine decarboxylase has been reported by some investigators to be a virulence marker for Aeromonas species. Congo red uptake did not correlate with either acetyl methyl carbinol or lysine decarboxylase production in our study. These data suggest that Congo red uptake may not be a useful marker for virulence of motile Aeromonas species.
Role of interleukin-1 in augmenting serum neutralization of bacterial lipopolysaccharide
Authors: Riveau G R , Novitsky T J , Roslansky P F , Dinarello C A , Warren H S
Published: January 2020

We have previously described an assay to quantify the serum neutralization of bacterial lipopolysaccharide which is based on a spectrophotometric Limulus amoebocyte lysate test (T.J. Novitsky, P.F. Roslansky, G.R. Siber, and H.S. Warren, J. Clin. Microbiol. 21:211-216, 1985). Studies since have shown that serum samples drawn from patients with leukemia and fever, gram-negative or gram-positive bacterial infections, or shock caused by gram-negative bacteria neutralize approximately 10-fold more lipopolysaccharide than do samples from normal controls. These findings suggested that the increased neutralization might reflect an acute-phase response and raised the question of whether it might be under the control of interleukin-1. To answer this question, we studied the neutralization of lipopolysaccharide in serum samples drawn from rabbits before and after the administration of crude interleukin-1, prepared from activated macrophage supernatants, and recombinant human interleukin-1. Crude interleukin-1 induced a 5.7-fold increase in serum neutralization 24 h after intravenous injection, and cloned interleukin-1 induced a 3.0-fold increase (P less than or equal to 0.01 and 0.05, respectively). In individual rabbits given identical doses of crude interleukin-1 on a weight basis, the serum-neutralizing ability correlated significantly with three activities of interleukin-1: rise in temperature (r2 = 0.558; P less than or equal to 0.01), decrease in serum iron (r2 = 0.534; P less than or equal to 0.01), and increase in serum copper (r2 = 0.323; P less than or equal to 0.05). We conclude that the increase in neutralization of bacterial lipopolysaccharide by serum samples drawn from patients with inflammatory states is mediated, at least in part, by interleukin-1, presumably through the induction of acute-phase serum proteins.