bluuebunny/crossref_metadata_2025 huggingface dataset:
Laboratory investigation of outbreak of hemorrhagic colitis caused by Escherichia coli O157:H7
Authors: Krishnan C , Fitzgerald V A , Dakin S J , Behme R J
Published: January 2020

A severe outbreak of hemorrhagic colitis occurred in London, Ontario, during the month of September 1985. A total of 55 residents and 18 employees of a nursing home developed diarrhea, and 17 residents (age range, 78 to 99 years) died. Specimens from 38 patients, 37 employees and contacts, and 10 autopsies were investigated for all enteric pathogens. Specimens were also planted on MacConkey-sorbitol agar. Fecal extracts were tested on Vero cells for cytotoxin (FVT). Escherichia coli isolates were serotyped and tested for verotoxin and beta-glucuronidase production. Of the 38 symptomatic patients, 26 were positive for FVT, verotoxin-producing E. coli (VTEC), or both. Of the 105 specimens that were examined from these 38 patients, FVT and VTEC were both positive in 30 specimens, FVT only was positive in 13 specimens, and VTEC only was positive in 4 specimens. None of the 27 specimens from 10 autopsies was positive for FVT or VTEC. No other enteric pathogen was found in any of the cases. All asymptomatic individuals were negative for both FVT and VTEC. Of 19 VTEC strains that were isolated, 18 belonged to serotype O157:H7. These 18 strains and 2 more strains that were obtained from sporadic cases that had occurred within the 2 previous months were found to give similar biochemical reactions in a 36-test identification system. All isolates of serotype O157:H7 were beta-glucuronidase negative and susceptible to the antimicrobial agents that are used to treat E. coli infections. Testing for FVT and VTEC was found to be the most sensitive and specific technique for the laboratory diagnosis of this disease. Negative sorbitol, positive raffinose, and negative beta-glucuronidase tests appeared to be consistent markers for aiding in the detection of E. coli O157:H7.
Comparison of enzyme-linked immunosorbent assay and complement fixation and indirect fluorescent-antibody tests for detection of Coxiella burnetii antibody
Authors: Péter O , Dupuis G , Peacock M G , Burgdorfer W
Published: January 2020

An enzyme-linked immunosorbent assay (ELISA) was developed to detect immunoglobulin G to Coxiella burnetii phase II. Serum samples from 213 patients who had had Q fever 1 year previously and from 301 blood donors from six localities in Switzerland were tested by ELISA and by indirect fluorescent-antibody (IFA) and complement fixation (CF) tests. The ELISA and the IFA and CF tests detected antibody to C. burnetii in 202 (94.8%), 193 (90.6%), and 166 (77.8%) of the 213 Q fever patients, respectively. With the serum samples from blood donors, the ELISA yielded a higher percentage of positive sera than did the IFA and CF tests. The high specificity of the three tests was confirmed by analyzing paired serum samples from 36 patients suffering from acute pneumonia of viral or bacterial origin. In these cases, the serological results were negative by the three tests, except for three Q-fever cases included as positive control.
Interleukin 2 and gamma interferon production, interleukin 2 receptor expression, and DNA synthesis induced by tularemia antigen in vitro after natural infection or vaccination
Authors: Karttunen R , Andersson G , Ekre H P , Juutinen K , Surcel H M , Syrjälä H , Herva E
Published: January 2020

The T-cell response induced by Francisella tularensis antigen in sensitized subjects was characterized in vitro by measuring DNA synthesis in whole-blood and mononuclear cell cultures, interleukin 2 (IL-2) and gamma interferon (IFN-gamma) production, and IL-2 receptor expression. Correlations between these variables were estimated. The strengths of the responses were compared in 21 subjects naturally infected 2 years ago, 6 subjects vaccinated 5 to 6 years ago, and 13 control subjects with no history of infection or vaccination. Subjects with a history of natural infection synthesized more DNA in both whole-blood and mononuclear cell cultures, secreted more IL-2 and IFN-gamma, and expressed more IL-2 receptors than control subjects did. All these responses differed highly significantly (P less than 0.001) from those of the control subjects. The vaccinees exhibited somewhat lower responses than the naturally immunized subjects did, but the vaccinees could be distinguished from the control subjects by their DNA synthesis, receptor expression, and IFN-gamma production (P less than 0.01 to 0.001). The vaccinees showed a lower response, in terms of DNA synthesis and IL-2 secretion (P less than 0.05), than the infected group did but responded in a manner similar to that of this group, with respect to receptor positivity and IFN-gamma secretion (P greater than 0.10). The correlations between all the T-cell functions were good, with highly significant correlations (P less than 0.001) between whole-blood DNA synthesis and IL-2 and IFN-gamma secretion and between the two lymphokines (P less than 0.001). The results not only increase our knowledge of the T-cell response to tularemia antigen but also give an alternative approach to DNA synthesis measurement for the quantitation of T-cell responses. The results for the low-responding sensitized subjects seem to indicate that the parameters were comparable in sensitivity.
Regression analysis, proposed interpretative zone size standards, and quality control guidelines for a new macrolide antimicrobial agent, A-56268 (TE-031)
Authors: Hanson C W , Bailer R , Gade E , Rode R A , Fernandes P B
Published: January 2020

A-56268 is a 6-O-methyl derivative of erythromycin A which has a spectrum of activity similar to that of erythromycin and is 1 log2 dilution more potent than erythromycin against most organisms that have been tested. The correlation of zone size diameters and MICs of A-56268 for 461 strains of bacteria isolated from clinical specimens was investigated. Based on anticipated levels in human serum of 2 micrograms/ml, 15-microgram disks have been recommended with zone size standards of greater than or equal to 15 mm for susceptibility (MIC correlate, less than or equal to 2.0 micrograms/ml) and less than or equal to 11 mm for resistance (MIC correlate, greater than or equal to 8 micrograms/ml). Selection of these tentative breakpoints resulted in no very major errors (false susceptible), a major error (false resistant) rate of 0.22%, and an acceptable minor error (intermediate) rate of 2.82%. MIC ranges and zone diameter limits for quality control organisms used in the standardized agar dilution and disk diffusion susceptibility tests with A-56268 are given.
Systemic and intestinal immunities after natural typhoid infection
Authors: Sarasombath S , Banchuin N , Sukosol T , Rungpitarangsi B , Manasatit S
Published: January 2020

A 2-year study of systemic and intestinal immunity to Salmonella typhi was performed in 14 patients who were suffering from typhoid fever in an attempt to extrapolate the mechanism of immune responses in this disease. The methods employed were the leukocyte migration inhibition agarose test for the measurement of systemic cell-mediated immunity. The systemic immunoglobulin G (IgG) and IgM that were specific to S. typhi and anti-O and anti-H agglutinins were measured by indirect enzyme-linked immunosorbent assay (ELISA) and the Widal test, respectively. The immunobead ELISA was used to measure total secretory IgA (SIgA), and indirect ELISA was used to measure SIgA that was specific to S. typhi in the intestinal lavage fluid. The results revealed that the patients developed various types of immune response to S. typhi that had various magnitudes and durations. After the onset of illness, the cell-mediated immunity persisted for 16 weeks; IgG, IgM, and anti-O and anti-H agglutinin persisted for 2 years, 16 weeks, 16 weeks, and 36 weeks, respectively. SIgA can persist in the gut for about 48 weeks. Thus, the immunities as a whole can barely persist beyond 1 year after the onset of illness, unless there are persistent booster stimulations by S. typhi bacilli that exist in the environment, and then the immunities may be lifelong.
Comparison of selective and nonselective media for recovery of Campylobacter pylori from antral biopsies
Authors: Krajden S , Bohnen J , Anderson J , Kempston J , Fuksa M , Matlow A , Marcon N , Haber G , Kortan P , Karmali M
Published: January 2020

Antral biopsy specimens from patients with acid peptic disease were cultured in parallel on Skirrow medium (SM) and sheep blood agar (SBA) for Campylobacter pylori. In institution 1, 23 of 88 (26.1%) endoscopies were positive on SBA compared with 37 of 88 (42.0%) on SM (P = 0.0001). In institution 2, 29 of 49 (59.2%) endoscopies were positive for C. pylori on SBA and 27 of 49 (55.1%) were positive on SM (P = 0.50). The addition of SM optimizes the recovery of C. pylori from antral biopsy specimens.
Diagnosis of ear canker in dogs by bacterial-colony displacement
Authors: Goldsmid J M , Thomson K , Gandy D
Published: January 2020

The diagnosis of a case of ear canker in a dog by bacterial-colony displacement is described. In this case, the causative mite was detected on the primary plates inoculated from a bacterial swab. This result indicates that the phenomenon of bacterial-colony displacement should be noted and investigated in diagnostic laboratories, as it indicates the presence of a range of motile metazoan parasites which may prove to be of clinical significance.
Latex agglutination test for screening of Haemophilus influenzae type b carriers
Authors: Heikkilä R , Takala A , Käyhty H , Leinonen M
Published: January 2020

Latex agglutination (LA) for the demonstration of Haemophilus influenzae type b capsular antigen in nasopharyngeal swabs was applied to the screening of H. influenzae type b carriers and compared with culturing by the antiserum agar method on Levinthal-bacitracin plates. Altogether, 51 (33%) of the 154 nasopharyngeal specimens collected from the close contacts of patients with invasive H. influenzae type b disease were positive in LA or the antiserum agar method or both. All 40 culture-positive samples were also positive in LA, and in 11 (9.6%) culture-negative samples, H. influenzae type b antigen was demonstrated by LA. LA as used in the present study is cheap, rapid, and easy to perform and is thus an ideal tool for the screening of H. influenzae type b carriers.
Detection of specific serum immunoglobulin M in nephropathia epidemica (Scandinavian epidemic nephropathy) by a biotin-avidin-amplified immunofluorescence method
Authors: Settergren B , Juto P , Wadell G
Published: January 2020

A biotin-avidin-amplified indirect immunofluorescence method was used to demonstrate specific serum immunoglobulin M (IgM) antibodies in nephropathia epidemica, the Scandinavian type of hemorrhagic fever with renal syndrome. The antigen in the test was the cross-reacting agent of Korean hemorrhagic fever, Hantaan virus. Sixty-two serum samples from 15 patients with clinically typical nephropathia epidemica were analyzed. Eleven patients had specific IgM in one or more serum samples. The IgM could be demonstrated from day 2 up to day 37, and all patients had detectable specific IgM within 15 days after the onset of disease. In 49 control serum samples, no specific IgM could be detected, indicating a high specificity for the method. The findings demonstrate that the biotin-avidin-amplified immunofluorescence IgM assay is a useful tool in the diagnosis of early nephropathia epidemica disease.
Evaluation of anaerobic microdilution MIC results with the Prompt Inoculation System
Authors: Mangels J I
Published: January 2020

The Prompt Inoculation System (3M Co.) was compared with the overnight suspension inoculation procedure used with a broth microdilution anaerobic commercial system (Micro-Media Systems) for differences in MIC. MIC results from both suspension methods using six National Committee for Clinical Laboratory Standards-recommended quality control organisms were identical in 18 instances (75%) and within +/- 1 log2 dilution in 96% of the comparisons. Results with 45 anaerobic clinical isolates also compared satisfactorily; 83% of the results were identical and 97% were within +/- 1 log2 dilution. In addition, the direct (Prompt)-inoculated microdilution trays produced better growth and more valid MIC results; 92% of the clinical isolates produced MIC results versus 79% by the overnight suspension procedure.
Rapid identification of obligately anaerobic gram-positive cocci using high-performance liquid chromatography
Authors: Harpold D J , Wasilauskas B L
Published: January 2020

High-performance liquid chromatography was evaluated as a rapid means of identifying obligately anaerobic gram-positive cocci of medical interest. Isolates were inoculated into a defined chemical medium consisting primarily of amino acids and were incubated aerobically for 1 h at 35 degrees C. After removal of organisms, the supernatant fluids were derivatized for 1 min at room temperature by the addition of o-phthalaldehyde. The total time required to run a chromatogram was approximately 50 min. Standardized peak heights for each medium component and any new peaks formed were calculated for each isolate and compared with those for uninoculated control medium. Multiple isolates of various species of anaerobic gram-positive cocci gave consistent patterns of medium utilization that could be used for identification purposes. This method can easily be adapted for laboratory use and has the potential for automated microbial identification.
Novel color test for rapid detection of group A streptococci
Authors: Hadfield S G , Petts D N , Kennedy P , Lane A , McIllmurray M B
Published: January 2020

A novel color test for the rapid detection of group A streptococci has been developed. The test, designed to be suitable for use in clinical laboratories as well as by less experienced personnel, incorporates the simplicity of latex tests with a color change to indicate the presence of group A streptococcal antigen. The test, which takes 5 min, was evaluated with 646 throat swabs, with a 15.6% incidence of group A streptococci; for swabs which yielded 10 or more group A streptococcal colonies in cultures, the sensitivity was 96.8%, and the specificity was 99.1%. In addition, the color test was 100% sensitive and specific when used to detect group A streptococcal antigen in beta-hemolytic colonies from culture plates.
Usefulness of an enzyme-linked immunosorbent assay for detection of Giardia antigen in feces
Authors: Nash T E , Herrington D A , Levine M M
Published: January 2020

The usefulness of a recently developed enzyme-linked immunosorbent assay which detects Giardia lamblia antigen in feces was determined in experimentally infected humans. Giardia antigen was determined in serially collected fecal specimens from humans inoculated with two Giardia isolates, GS/M and Isr. A total of 277 stools from 18 volunteers were tested, 74 from Isr-inoculated volunteers and 203 from GS/M-inoculated volunteers. None of the five Isr-inoculated volunteers became infected, and none of their stools contained Giardia antigen. In contrast, all of the 13 GS/M-inoculated volunteers became infected, and Giardia antigen was present one or more times in the stools of each. Of 203 stools from GS/M-inoculated volunteers, 73 contained Giardia cysts, and 69 of these (94.5%) had detectable antigen. In contrast, 108 of the 203 specimens were positive for Giardia antigen and only 73 had cysts. Most antigen-positive but cyst-negative specimens occurred during treatment, but during patency 71 stools contained antigen and 65 had cysts. The enzyme-linked immunosorbent assay is infections and is easier to perform.
Identification of group B streptococcal antigen with lectin-bound polystyrene particles
Authors: Slifkin M , Cumbie R
Published: January 2020

The lectin of the tomato, Lycopersicon esculentum, or of the potato, Solanum tuberosum, can be passively coupled to amide-modified polystyrene spheres to be used as a detection reagent for the specific identification of group B streptococcal cultures grown in selective or nonselective Todd-Hewitt broth for 5 and 4 h, respectively. Agglutination occurred when the lectin reagents were allowed to react with either the cell suspension, clarified broth, or antigen extracts from group B streptococci grown in Todd-Hewitt broth. No agglutination occurred when these lectins were allowed to react with strains of serogroup A, C, D, F, or G streptococci. False-negative agglutination responses may occur with certain serotype of group B streptococci grown on Columbia sheep blood agar. A 20-min staining time permitted the specific labeling of fixed smears of group B streptococci with fluorescein-conjugated Lycopersicon lectin. The lectin from the solanaceous plant Datura stramonium did not agglutinate group B streptococci or other clinically significant streptococcal serogroups.
Immunodiagnosis of human cysticercosis (Taenia solium) with antigens purified by monoclonal antibodies
Authors: Nascimento E , Tavares C A , Lopes J D
Published: January 2020

Monoclonal antibodies were generated from mice immunized with scolex protein antigen of Cysticercus cellulosae. Three monoclonal antibodies specific for cysticercal antigens, which did not show any cross-reactivity with Taenia solium or Taenia saginata antigens, were selected. Each monoclonal antibody coupled to Sepharose could purify one antigen, which appeared as a single band on polyacrylamide gel electrophoresis. When antigens purified by monoclonal antibodies were used to detect antibody in serum samples taken from patients with cysticercosis, taeniasis, and other parasitic infections in an enzyme-linked immunosorbent assay, cross-reactivity was observed until a serum dilution of 1:128 was reached. Since serum samples from unexposed subjects showed positive reactions until a dilution of 1:64 was reached, we chose a discriminative dilution (1:128) above which no cross-reaction was observed. The percent positive serum samples from cysticercosis patients was 100% by the enzyme-linked immunosorbent assay with any of the antigens purified by monoclonal antibodies.
Disposable reversed-phase chromatography columns for improved detection of carboxylic acids in body fluids by electron-capture gas-liquid chromatography
Authors: Daneshvar M I , Brooks J B , Winstead R M
Published: January 2020

Disposable reversed-phase chromatography columns were tested for their effectiveness in removing unreacted trichloroethanol (TCE) from derivatized samples for gas-liquid chromatography analysis. Derivatized acidic chloroform extracts of saponified whole cells of Mycobacterium species, spent culture media, and derivatized acidic chloroform extracts of serum and cerebrospinal fluids from patients with tuberculous meningitis were tested. Samples were added to preconditioned reversed-phase chromatography columns, and various solvents and solvent mixtures were tested to determine maximum recovery of the TCE derivatives. With this procedure, we were able to quickly remove the TCE reagent and efficiently recover TCE-derivatized carboxylic acids. Use of these columns improved the reagent cleanup procedure, simplified the derivatization step, permitted increased detection of trace components, such as tuberculostearic acid, in body fluids, and improved the selectivity of the procedure for detection of carboxylic acids.
Susceptibility of Aedes albopictus C6/36 cells to viral infection
Authors: White L A
Published: January 2020

The susceptibility of the C6/36 clone of Aedes albopictus monolayer cell cultures was determined with 46 prototype viruses passed through three subcultures. Viral growth was confirmed by titration of the passage material in other susceptible host systems. Nineteen viruses demonstrated good growth in C6/36 cells: coxsackievirus group A type 10 and group B types 2, 3, 4, and 5; enterovirus 69; mumps virus; poliovirus types 1 to 3; reovirus types 1 to 3; vaccinia virus; dengue virus type 2; eastern equine encephalomyelitis virus; La Crosse virus; Rocio virus; and St. Louis encephalitis virus. Ten viruses did not adapt to growth in the C6/36 cultures. Seventeen other virus strains displayed only limited growth which was primarily restricted to the initial C6/36 passage or was detected by hemagglutinin reactions without observable cell degeneration. Of the 46 viruses, 33 (72%) were capable of initiating infection with a demonstrable cytopathic effect in the initial C6/36 passage. Hemagglutination or complement fixation titers or both were obtained with dengue virus type 2, eastern equine encephalomyelitis virus, La Crosse virus, mumps virus, reovirus types 1 to 3, and Rocio, St. Louis encephalitis, and vaccinia viruses.
Prevalence of thymidine-dependent Staphylococcus aureus in patients with cystic fibrosis
Authors: Gilligan P H , Gage P A , Welch D F , Muszynski M J , Wait K R
Published: January 2020

During a 1-year period, the prevalence of thymidine-dependent (TD) Staphylococcus aureus in patients at two geographically distinct cystic fibrosis (CF) centers was determined. Of 200 CF patients who had their respiratory secretions cultured, 95 harbored S. aureus, and 20 (21%) had TD S. aureus as their predominant staphylococcal isolate. All 20 TD S. aureus-positive patients had received trimethoprim-sulfamethoxazole for an average of 30.9 months. It was also observed that TD S. aureus exhibited aberrant colony morphologies or did not grow on media commonly used in CF centers for S. aureus isolation, suggesting that this organism could be missed by routine culture methods. In contrast, all 20 isolates had typical staphylococcal morphology on mannitol salt agar after 48 h of incubation. Mannitol salt agar is recommended for primary isolation of TD S. aureus.
Genetic relatedness among human rotavirus genes coding for VP7, a major neutralization protein, and its application to serotype identification
Authors: Midthun K , Flores J , Taniguchi K , Urasawa S , Kapikian A Z , Chanock R M
Published: January 2020

Antigenic characterization of human rotaviruses by plaque reduction neutralization assay has revealed four distinct serotypes. The outer capsid protein VP7, coded for by gene 8 or 9, is a major neutralization protein; however, studies of rotaviruses derived from genetic reassortment between two strains have confirmed that another outer capsid protein, VP3, is in some cases equally important in neutralization. In this study, the genetic relatedness of the genes coding for VP7 of human rotaviruses belonging to serotypes 1 through 4 was examined by hybridization of their denatured double-stranded genomic RNAs to labeled single-stranded mRNA probes derived from human-animal rotavirus reassortants containing only the VP7 gene of their human rotavirus parent. A high degree of homology was demonstrated between the VP7 genes of strain D and other serotype 1 human rotaviruses, strain DS-1 and other serotype 2 human rotaviruses, strain P and other serotype 3 human rotaviruses, and strain ST3 and other serotype 4 human rotaviruses. Hybrid bands could not be demonstrated between the VP7 gene of D, DS-1, P, or ST3 and the corresponding gene of human rotaviruses belonging to a different serotype. RNA specimens extracted from the stools of 15 Venezuelan children hospitalized with rotavirus diarrhea were hybridized to each of the reassortant probes representing the four human serotypes. All five viruses with short RNA patterns showed homology with the DS-1 strain VP7 gene; two of these were previously adapted to tissue culture and shown to be serotype 2 strains by tissue culture neutralization. Of the remaining 10 viruses with long RNA patterns, 2 hybridized only to the D strain VP7 gene, 6 hybridized only to the P strain VP7 gene, and 2 hybridized only to the ST3 strain VP7 gene. Hybridization using single human rotavirus gene substitution reassortants as probes may provide an alternative method for identifying the VP7 serotype of field isolates that would circumvent the need for tissue culture adaptation.
Comparative studies on use of fresh and frozen peripheral blood lymphocyte specimens for isolation of human immunodeficiency virus and effects of cell lysis on isolation efficiency
Authors: Gallo D , Kimpton J S , Dailey P J
Published: January 2020

Heparinized blood specimens (n = 44) and frozen peripheral blood lymphocyte (PBL) specimens (n = 42) were used to evaluate the effects of lysis on human immunodeficiency virus (HIV) isolation. In the two respective groups, 17 and 27 specimens were HIV antibody positive. In the first group there were 8 and in the second group there were 25 that were symptomatic and were classified as indicating an acquired immunodeficiency syndrome-related condition or a pre-acquired immunodeficiency syndrome-related condition by the Centers for Disease Control definition. One-half of the cells from each specimen were frozen and thawed three times before cocultivation with uninfected lymphocytes, and the isolation rates from whole and lysed cells were compared. HIV was isolated from 15 (88%) of 17 fresh specimens and from 24 (89%) of 27 frozen PBLs from HIV antibody-positive patients, and lysis had no overall effect on the isolation rate, which suggested that frozen PBLs were as suitable as fresh blood for HIV isolation attempts and that it was not necessary to maintain cell integrity when submitting PBL samples. Of 21 asymptomatic patients, 20 were culture positive, and of 23 symptomatic patients, 19 were culture positive. Specimens from the 42 antibody-negative individuals were culture negative.
Inhibition of growth and swarming of Proteus mirabilis and Proteus vulgaris by triclosan
Authors: Firehammer B D
Published: January 2020

The MICs of triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) and the effect on swarming were determined for 35 isolates of Proteus mirabilis and 7 isolates of P. vulgaris of animal origin. Both species were susceptible to the antimicrobial agent, and growth of all but one isolate was inhibited by less than 1 microgram/ml in broth and on agar without blood. Swarming was inhibited at triclosan concentrations two- to fourfold less than the MICs. Higher concentrations were required with blood agar than with plain agar for inhibition of growth and swarming.
Serial propagation of porcine group C rotavirus (pararotavirus) in primary porcine kidney cell cultures
Authors: Terrett L A , Saif L J
Published: January 2020

A porcine group C rotavirus was adapted to serial propagation in roller tube cultures of primary porcine kidney cells with high concentrations of pancreatin. Infected cells were identified by immunofluorescence staining of cell monolayers. Only group C rotavirus particles were observed in culture supernatants by immune electron microscopy.
Extensive Actinomyces naeslundii infection in a child
Authors: Dobson S R , Edwards M S
Published: January 2020

A case of extensive Actinomyces naeslundii infection in a globally retarded patient is reported. To our knowledge, this uncommon Actinomyces species has not previously been described as a cause of widespread disease. Mental retardation and thoracic scoliosis were identified as features predisposing to infection.
Plasmid analysis as a means of strain differentiation in Clostridium perfringens
Authors: Mahony D E , Stringer M F , Borriello S P , Mader J A
Published: January 2020

A total of 114 Clostridium perfringens isolates were serotyped and examined for plasmids. Fifty-two strains were from hospitalized patients with diarrhea or from hospital environments, and 62 epidemiologically unrelated isolates were obtained from food poisoning outbreaks. All strains were screened for bacteriocin production against a common indicator strain of C. perfringens. In the one significant hospital outbreak of C. perfringens diarrhea, three to five plasmid types were found in strains of the predominant serotype, but no similar correlation between serotype and plasmid type was found in random isolates from a variety of sources. All of the strains associated with the diarrhea outbreak produced bacteriocins, whereas 63% of the strains from various sources produced bacteriocins. The typing data suggest a promising differentiating capability for plasmid analysis in the epidemiological study of outbreaks of food poisoning, diarrhea, or infections caused by C. perfringens.
Cell surface antigen of encapsulated Staphylococcus epidermidis ATCC 31432
Authors: Ohshima Y , Ichiman Y , Usui Y , Ko H L , Beuth J , Pulverer G , Yoshida K
Published: January 2020

The cell surface antigen (CSA) from encapsulated Staphylococcus epidermidis ATCC 31432 was isolated and fractionated by DEAE-Sephadex ion-exchange chromatography. It yielded a single precipitin line against rabbit antiserum and was composed of galactose, glucosamine, and two (so far) unidentified carbohydrates linked to a protein backbone. Glycerol could not be detected. In an experimental mouse infection, CSA showed some protective activities, enhancing the stimulation of granulocytes as well as the immunoglobulin M response. Apparently, CSA is different from teichoic acid.
Differentiation of motile and mesophilic Aeromonas strains into species by testing for a CAMP-like factor
Authors: Figura N , Guglielmetti P
Published: January 2020

Motile and mesophilic Aeromonas strains can presumptively be differentiated into species in 18 to 24 h by testing the isolates for the production of a CAMP-like factor. Aeromonas hydrophila strains were positive either aerobically or anaerobically, Aeromonas sobria strains were positive only aerobically, and Aeromonas caviae strains were always negative.
Commercial latex agglutination tests for detection of Haemophilus influenzae type b and Streptococcus pneumoniae antigens in patients with bacteremic pneumonia
Authors: Ajello G W , Bolan G A , Hayes P S , Lehmann D , Montgomery J , Feeley J C , Perlino C A , Broome C V
Published: January 2020

The validity of commercial latex agglutination kits for detection of Haemophilus influenzae type b and Streptococcus pneumoniae antigens in serum and urine specimens was studied. We tested serum and urine specimens from 44 patients with bacteremic pneumonia (23 S. pneumoniae, 13 H. influenzae type b, 11 other) with commercial latex agglutination kits (Directigen, Bactigen) for S. pneumoniae and H. influenzae type b antigens. All specimen samples were randomized and read blindly by two readers. Interreader reproducibility was 100%. The sensitivity and specificity of both kits for H. influenzae type b antigens in serum and urine were greater than 90%. None of the 24 urine samples from S. pneumoniae bacteremic patients were positive by either kit, although 6 ng of type 3 polysaccharide could be detected in spiked urine. Sensitivity for S. pneumoniae antigens in serum was 27% for Directigen and 38% for Bactigen. Specificity for S. pneumoniae antigens in serum was 95% for Directigen and 74% for Bactigen. The results suggest that the kits are useful in diagnosing H. influenzae type b pneumonia. However, the commercially available S. pneumoniae reagents tested appear to have limited utility for diagnosing S. pneumoniae pneumonia because both kits lack sensitivity and Bactigen lacks specificity, as well.
Association of Pseudomonas and Serratia corneal ulcers with use of contaminated solutions
Authors: Mayo M S , Schlitzer R L , Ward M A , Wilson L A , Ahearn D G
Published: January 2020

The wetting and soaking solutions and contact lens cases of eye clinic patients commonly were contaminated with gram-negative bacteria during their use. Serratia marcescens occurred most frequently in preserved solutions, whereas Pseudomonas aeruginosa was most often recovered from home-prepared saline. The bacteria were recovered at densities of greater than 10(6) cells per ml and typically persisted in the solutions. Eight patients who developed bacterial keratitis during 1986 used solutions contaminated with the etiological agents of the infections. Improper hygienic practices of the patients and failure of some preservative systems were implicated in the development of the infections.
Impact of cell culture sensitivity and virus concentration on rapid detection of herpes simplex virus by cytopathic effects and immunoperoxidase staining
Authors: Zhao L S , Landry M L , Balkovic E S , Hsiung G D
Published: January 2020

Tremendous interest has been generated in the commercial kits now available that incorporate herpes simplex virus isolation in cell culture with immunoperoxidase staining for viral antigen detection. Most studies comparing commercial kits with conventional cell culture techniques have found the kits to be less sensitive. However, different cell cultures were used for the two methods. In this study, mink lung, rabbit kidney, MRC-5, and Vero cells were compared for reisolation of herpes simplex virus from clinical specimens in which viral infectivity titers were concurrently determined. When specimens contained high titers of infectious virus, the cell system used made little difference and all specimens were detected by immunoperoxidase staining at 48 h postinoculation. However, when specimens contained low concentrations of virus, the differences in sensitivity between cell systems became apparent in rapidity of detection and overall isolation rate. Mink lung and rabbit kidney cells were both more sensitive than MRC-5 cells; Vero cells were significantly less sensitive than the other cells tested. The application of immunoperoxidase staining shortened the time to virus detection and lessened, but did not eliminate, the differences between the cell systems. Cytopathic effects alone in the most sensitive cell system equaled or exceeded immunoperoxidase staining applied in less-sensitive cell cultures.
Candida tropicalis infection in normal, diabetic, and neutropenic mice
Authors: Fromtling R A , Abruzzo G K , Giltinan D M
Published: January 2020

Opportunistic infections caused by Candida tropicalis have been noted with increasing frequency in compromised patients. The pathogenicity of three isolates of C. tropicalis was studied in normal CD-1 mice, streptozotocin-induced diabetic mice, and cyclophosphamide-induced neutropenic mice. Lethal dose 50% endpoints and quantitative distribution of yeast cells in spleen, liver, and kidneys of mice infected intravenously were determined. The virulence of one yeast isolate was greater than that of the other two. The order of susceptibility to mortality and degree of organ colonization was neutropenic greater than diabetic greater than normal. Renal lesions resembling those associated with infection by C. albicans appeared by day 5 postinfection in diabetic and neutropenic mice. Greater numbers of C. tropicalis yeast cells were isolated from homogenates of the affected kidneys, suggesting that the kidney is a target organ for this fungus. This study demonstrates the increased susceptibility of compromised mice to C. tropicalis as compared with normal mice and verifies the ability of these yeasts to cause opportunistic disease.
Identification of enterotoxigenic Escherichia coli with synthetic alkaline phosphatase-conjugated oligonucleotide DNA probes
Authors: Seriwatana J , Echeverria P , Taylor D N , Sakuldaipeara T , Changchawalit S , Chivoratanond O
Published: January 2020

Alkaline phosphatase-conjugated (AP) 26-base oligonucleotide DNA probes were compared with the same probes labeled with gamma-32P for the identification of heat-labile (LT) and heat-stable (ST) enterotoxigenic Escherichia coli (ETEC). The AP oligonucleotide probes were as sensitive as the radiolabeled (RL) probes in detecting LT and STA-2 target cell DNA, but the AP ST probe, which differed from STA-1 by two bases, was less sensitive than the RL probe in detecting STA-1 DNA (6.25 versus 0.78 ng). Of 94 ETEC that were identified with the RL probe, the AP probes detected 93% (28 of 30) of ST, 73% (25 of 34) of LT, and 67% (20 of 30) of LTST ETEC. When colony lysates of these ETEC were examined, the AP probes identified all 94 ETEC. In examinations of stool blots, the RL and AP probes were shown to have sensitivities of 71 and 59%, specificities of 91 and 86%, positive predictive values of 87 and 73%, and negative predictive values of 86 and 74%, respectively. AP oligonucleotide probes to detect ETEC were less sensitive in detecting ETEC by colony or stool blot hybridization than the RL probes but could be used by laboratories without access to radioisotopes to examine colony lysates.
Production of toxic shock syndrome toxin 1 by Staphylococcus aureus restricted to endogenous air in tampons
Authors: Reiser R F , Hinzman S J , Bergdoll M S
Published: January 2020

All types of four brands of tampons were tested in triplicate by a tampon sac method for their effect on production of toxic shock syndrome toxin 1 (TSST-1). In this method the available air is limited to that which is in the tampon sac. Tampons were weighed and inserted into dialysis sacs inoculated with a TSST-1-producing Staphylococcus aureus strain; the sacs were submerged into brain heart infusion agar, which was allowed to harden around the sacs, and were incubated for 18 h at 37 degrees C. The tampons were removed, weighed, and extracted; the CFU of staphylococci and the amount of toxin present in the extracts were determined. Glass wool was used in place of the tampons as one control, and inoculated empty sacs were used as a second control. The total CFU were consistently greater than 2 X 10(11) for the tampons and glass wool and less than or equal to 10(11) for the empty sac control. Total toxin production for all tampons tested and the glass wool was 2 to 10 times higher than the toxin produced with the empty sac control. These results indicate that tampons provide increased surface area for the staphylococci to grow and adequate oxygen for toxin production. No significant inhibition of growth of the staphylococci or TSST-1 production by any of the tampons tested was noted.
In vitro chloramphenicol susceptibility testing of Haemophilus influenzae: disk diffusion procedures and assays for chloramphenicol acetyltransferase
Authors: Doern G V , Daum G S , Tubert T A
Published: January 2020

The activity of chloramphenicol against 100 different strains of Haemophilus influenzae was assessed by a macrotube broth dilution technique and by a standardized disk diffusion method using both enriched chocolate agar (CHOC) and Mueller-Hinton agar containing 1.0% hemoglobin and 1.0% IsoVitaleX (BBL Microbiology Systems, Cockeysville, Md.) supplement (CHOC-MHA). Filter disks containing 30 micrograms of chloramphenicol were used with the disk diffusion procedure. The following zone diameter interpretive criteria were defined: CHOC-MHA, less than or equal to 25 mm = resistant [corrected] and greater than or equal to 26 mm = susceptible [corrected]; CHOC, less than or equal to 28 mm = resistant [corrected] and greater than or equal to 29 mm = susceptible [corrected]. all of the H. influenzae strains examined were also characterized by using two rapid assays for chloramphenicol acetyltransferase (CAT) activity: a 1-h tube method (t-CAT) and a 30-min procedure which used commercially available reagent-impregnated disks (d-CAT). The t-CAT procedure was found to be significantly more accurate than the d-CAT procedure as a means for demonstrating production of CAT.
Unusual verotoxin-producing Escherichia coli associated with hemorrhagic colitis
Authors: Bopp C A , Greene K D , Downes F P , Sowers E G , Wells J G , Wachsmuth I K
Published: January 2020

All strains of Escherichia coli isolated from cases of hemorrhagic colitis and sent to the Centers for Disease Control, Atlanta, Ga., over a 3-year period were assayed for toxicity in Vero cell cultures. Strains that produced moderate or high levels of verotoxin were characterized by serotype, biotype, antimicrobial resistance, plasmid profile, and adherence to HeLa cells. Over 200 isolates were typical O157:H7 strains. Six isolates were atypical O157:H7 strains; two were resistant to antimicrobial agents; one was indole negative, two were citrate positive, and one was urea positive. Six isolates were nonmotile O157 strains. All of these isolates were similar to typical O157:H7 strains by plasmid profile and negative or slow sorbitol fermentation. Eleven other verotoxigenic isolates did not possess the O157 antigen, had a variety of plasmid profiles, and were sorbitol positive. Two of the eleven were enteropathogenic serotypes (O111:NM and O26:H11), yet none were adherent to HeLa cells. We conclude that verotoxigenic E. coli associated with hemorrhagic colitis includes atypical O157 strains and other serotypes. Hence, investigators should use current screening methods with caution.
Prevalence of Borrelia burgdorferi in white-footed mice and Ixodes dammini at Fort McCoy, Wis
Authors: Anderson J F , Duray P H , Magnarelli L A
Published: January 2020

Borrelia burgdorferi, the causative agent of Lyme disease, was isolated from 15 of 17 white-footed mice (Peromyscus leucopus) and 54 of 82 subadult Ixodes dammini from Fort McCoy, Wis. Of the 47 isolates tested, all reacted in indirect fluorescent-antibody tests with monoclonal antibodies directed against a surface protein of B. burgdorferi (approximate molecular weight, 31,000) and flagellins that are common to all Borrelia species. Indirect fluorescent-antibody reactions were variable when an antibody that binds to a surface protein with an approximate molecular weight of 34,000 was tested. The major proteins of isolates from ticks and mice had approximate molecular weights of 31,000, 34,000, and 41,000. Antibodies to B. burgdorferi were present (titer, greater than or equal to 1:64) in 16 of 97 white-tailed deer (Odocoileus virginianus). The mean number of subadult I. dammini on mice captured in June 1986 was 6.5, and the mean number of adult I. dammini on deer killed in November 1986 was 5.9. The presence of ticks and the high prevalence of I. dammini and mice infected with B. burgdorferi establish that Fort McCoy is an area in which the Lyme disease agent is highly endemic, even though there have been relatively few documented cases in humans. The low number of reported cases in humans may be a result of National Guard and reserve unit personnel returning home to civilian life and having symptoms expressed subsequently, or it could be due to misdiagnosis or nonreporting.
Isolation and analysis of restriction endonuclease digestive patterns of chromosomal DNA from Mycobacterium paratuberculosis and other Mycobacterium species
Authors: Whipple D L , Le Febvre R B , Andrews R E , Thiermann A B
Published: January 2020

A relatively rapid and efficient method for the extraction of chromosomal DNA from Mycobacterium paratuberculosis and other mycobacteria was developed. Approximately 25 to 50 micrograms of DNA could be extracted from 100 mg (wet weight) of cells, which was sufficient to perform several restriction endonuclease analyses from a single preparation. The DNA from five Mycobacterium species, including four strains of M. paratuberculosis and four strains of M. avium, was analyzed by this method. Digestion with the restriction endonucleases BstEII and PstI yielded the most definitive restriction patterns. For some strains, the restriction endonuclease analysis results were in agreement with the current identification of these organisms. The two strains of M. avium serotype 2 had identical fragment patterns. Similarly, the two strains of M. avium complex serotype 6 had identical fragment patterns. The three mycobactin-dependent M. paratuberculosis strains were very similar, whereas the mycobactin-independent M. paratuberculosis strain was more similar to the M. avium serotype 2 strains. Although many more cultures would need to be evaluated to determine correct groupings, the results of this study demonstrated the potential of restriction enzyme analysis for the differentiation of slowly growing mycobacteria.
Bacteremia caused by a lactose-fermenting, multiply resistant Salmonella typhi strain in a patient recovering from typhoid fever
Authors: Cohen S L , Wylie B A , Sooka A , Koornhof H J
Published: January 2020

A female patient suffered a typical attack of typhoid fever due to a lactose-negative, fully susceptible Salmonella typhi strain. During convalescence she became febrile, and a lactose-fermenting S. typhi strain resistant to ampicillin, chloramphenicol, tetracycline, and trimethoprim was isolated from blood culture. This isolated was shown to harbor a plasmid which cotransferred lactose fermentation and antibiotic resistance.
High incidence of hemolysin production by Enterococcus (Streptococcus) faecalis strains associated with human parenteral infections
Authors: Ike Y , Hashimoto H , Clewell D B
Published: January 2020

Hemolysin production, clumping (pheromone) response, transferability of the hemolytic trait, and drug resistance were examined in 97 clinical isolates of Enterococcus (Streptococcus) faecalis. The isolates were derived from various sources (i.e., urine, pus, vagina, sputum, bile, and blood), and approximately 60% were found to be hemolytic. About 85% of the hemolytic strains exhibited a clumping response, compared with about 49% of the nonhemolytic strains. Over 50% of the hemolytic strains carried transferable hemolysin determinants, and in no case were drug resistance genes linked. The hemolytic strains exhibited multiple drug resistance more frequently than did the nonhemolytic strains. In contrast to the high frequency of hemolysin producers among parenteral isolates, strains derived from fecal specimens of healthy individuals exhibited a low (17%) incidence of hemolysin production.
Epitope-specific antibody responses to virulent and avirulent feline infectious peritonitis virus isolates
Authors: Fiscus S A , Rivoire B L , Teramoto Y A
Published: January 2020

Feline infectious peritonitis virus (FIPV) has been isolated several times from infected cats. Some of these isolates vary markedly in their ability to cause disease. Specific-pathogen-free cats were inoculated with the avirulent FIPV-UCD-2 isolate or the extremely virulent FIPV-79-1146 isolate or both. After 1 month, cats which had received FIPV-79-1146 were either dead or showed clinical signs of FIP. All cats which received only FIPV-UCD-2 remained healthy up to 6 months after inoculation. Antibody-mediated immune enhancement of disease was not observed in cats which received FIPV-UCD-2 before inoculation with FIPV-79-1146. Monoclonal antibodies which recognized type-specific epitopes on each of the structural polypeptides of these two viruses were used in competitive-inhibition enzyme-linked immunosorbent assays to analyze the humoral immune responses of the cats. All cats produced antibodies to epitopes found on the homologous virus. In addition, cats inoculated with FIPV-79-1146 also produced antibodies which inhibited the binding of the anti-FIPV-UCD-2 E1 monoclonal antibody. One cat inoculated twice with FIPV-UCD-2 produced antibodies which inhibited the binding of the anti-FIPV-79-1146 N- and E1-specific monoclonal antibodies. Competitive enzyme-linked immunosorbent assays may prove useful in distinguishing cats which are infected with virulent FIPV isolates from cats infected with avirulent feline coronaviruses.