bluuebunny/crossref_metadata_2025 huggingface dataset:
Minimal inhibitory concentrations of antimicrobial agents against Aeromonas hydrophila determined with the Autobac MTS
Authors: Overman T L , Seabolt J P
Published: January 2020

Minimal inhibitory concentrations of seven antimicrobial agents for 22 strains of Aeromonas hydrophila were determined with the Autobac MTS procedure. The ranges of the minimal inhibitory concentrations were found to be similar to those obtained by a microdilution procedure. Depending upon the interpretive criteria used, there were discrepancies with carbenicillin, cephalothin, kanamycin, and tetracycline. It is recommended that the beta-lactam antibiotics ampicillin, carbenicillin, and cephalothin not be tested because of their lack of clinical usefulness, thus completely eliminating all of the significant discrepancies and reducing expendable costs by 50%.
Patterns of extracellular proline-specific endopeptidases in Legionella and Flavobacterium spp. demonstrated by use of chromogenic peptides
Authors: Berdal B P , Bøvre K , Olsvik O , Omland T
Published: January 2020

Some Legionella strains possess a strong extracellular proline-specific endopeptidase (PSE) activity. Using an enlarged selection of chromogenic peptides representing a variety of N-terminal amino-acids binding to a -prolyl-proline, paranitroanilide chain, PSE activity of Legionella and Flavobacterium strains was examined. Differences in PSE activity emphasized the importance of the chemical structure at the nonchromogenic end of the peptide substrates. There seem to be distinct patterns of N-terminal specificity of PSE in the two bacterial groups.
Single-strain regression analysis for determination of interpretive breakpoints for cefoperazone disk diffusion susceptibility testing
Authors: Kronvall G
Published: January 2020

A novel approach for setting interpretive breakpoints in disk diffusion antibiotic susceptibility testing according to determined minimum inhibitory concentration (MIC) limits is described, using the method of single-strain regression analysis. The procedure was tested on reference strains Staphylococcus aureus (ATCC 25923), Streptococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), and Pseudomonas aeruginosa (ATCC 27853), using published results from cefoperazone disk diffusion experiments. The correlation between logarithm of the disk content and inhibition zone diameter squared was linear, excluding three endpoint values. When constants A and B in the new regression line equation were calculated for the four strains, all four showed different regression lines. Zone diameters corresponding to various MICs were calculated for a disk content of 75 micrograms. The values obtained for the four strains were 20.1, 20.9, 24.9, and 25.8 mm, respectively, for an MIC of 16 micrograms/ml, and 15.7, 15.7, 22.3, and 17.9 mm, respectively, for an MIC of 64 micrograms/ml. The following zone diameter breakpoints were determined for the "I" (intermediate) category, using a 75-micrograms disk: S. aureus, 18 to 15 mm; S. faecalis, 23 to 13 mm; E. coli, 20 to 17 mm; and P. aeruginosa, 20 to 17 mm.
Rapid quantitative microenzyme-linked immunosorbent assay for tetanus antibodies
Authors: Sedgwick A K , Ballow M , Sparks K , Tilton R C
Published: January 2020

A rapid quantitative microenzyme-linked immunosorbent assay for the detection of immunoglobulin G antibodies to tetanus toxoid is described. The assay is performed in 2.5 h and detects antibody levels of between 0.1 and 6 U/ml. Quantitation of the antibody concentration is unique in that multiple serum dilutions are tested on a single patient, the results are plotted as an antibody dilution curve, and the area under the curve is integrated for a final concentration. Tests for immune status on sera from 77 individuals demonstrated tetanus antibody concentrations of greater than or equal to 0.1 U/ml in 92% of a pediatric group and 62% of an adult group. The microenzyme-linked immunosorbent assay procedure is reproducible and is useful for the determination of immune status and immunization response.
Antigenemia detected in human coccidioidomycosis
Authors: Weiner M H
Published: January 2020

To advance the serological diagnosis of coccidioidomycosis, a radioimmunoassay was developed to detect an antigen of Coccidioides immitis and evaluated with serum samples from patients and controls. The assay antigen was fractionated from a culture filtrate of C. immitis cells by Sephacryl S300 gel chromatography. The assay used preliminary acid-heat extraction to dissociate serum-bound antigen and staphylococcal protein A as an absorbent. Antigenemia was detected in five (56%) of nine patients with coccidioidomycosis. Three of four negative tests occurred with sera from patients who had already received antifungal chemotherapy. Antigenemia was not detected in 106 control patients and normal donors. One false-positive reaction was observed in a patient with histoplasmosis. In all nine patients with active coccidioidomycosis, anti-C. immitis antibodies were detected during the initial evaluation or in the follow-up. In summary, an immunoassay for C. immitis antigenemia was developed; antigenemia was detected in five (56%) of nine patients with active coccidioidomycosis and a positive test indicated active or persistent disease.
Dilution technique for isolation of Haemophilus from swine lungs collected at slaughter
Authors: Pijoan C , Morrison R B , Hilley H D
Published: January 2020

A total of 307 lungs obtained from a slaughterhouse were cultured by a dilution technique for the isolation of Haemophilus spp. The technique consisted of performing serial (10-fold) dilutions of the tissue samples to a dilution of 10(-5). Two selective media were used. L broth consisted of a basal brain heart infusion broth containing 5% horse serum, 5% yeast extract, and 100 micrograms of NAD and 0.5 microgram of lincomycin per ml. L-B broth was identical to L broth, except 1.5 microgram of bacitracin per ml was included. The broths were incubated overnight and then plated onto blood agar. A total of 83 (27%) isolates were obtained, and both media proved to be necessary, as a proportion of isolates grew in one of the media employed but not in the other. Of the isolates, 66.3% were urease positive and most of these (98%) were classified as "minor group" strains. Urease-negative strains (27.7%) were classified as Haemophilus parasuis.
Cultivation of Neisseria gonorrhoeae under low-oxygen conditions
Authors: Kellogg D S , Crawford J A , Callaway C S
Published: January 2020

Sixteen Neisseria gonorrhoeae strains were examined for their abilities to grow under reduced oxygen tension. Low oxygen tensions were developed by evacuation-replacement procedures in which anaerobes and oxidation-reduction indicators were used as controls. All strains survived 96 h in a medium reduced to below -125 mV without visible growth. Detectable growth occurred at 0.05% oxygen, and 33% of normal colony size under air (21% oxygen) was obtained at 0.15% oxygen. Population selection did not determine survival and growth, but carbon dioxide was required. Characteristic colony morphologies were not evident at the lower oxygen concentrations. Colonial variation was not influenced during survival under anaerobic conditions or growth under low oxygen levels (0.15%). Medium differences were not significant affectors. We concluded that N. gonorrhoeae will grow under tensions suitable for anaerobes, and will demonstrate certain modifications of behavior under these conditions.
Techniques for the recovery and identification of Cryptosporidium oocysts from stool specimens
Authors: Garcia L S , Bruckner D A , Brewer T C , Shimizu R Y
Published: January 2020

Due to increasing numbers of patients with documented infections with Cryptosporidium and other coccidia, it is important for the physician and clinical laboratory to be aware of the appropriate diagnostic techniques necessary for organism recovery and identification. Although Cryptosporidium is found in the gastrointestinal tract, tissue biopsies may be insufficient for organism recovery; the examination of stool specimens is a noninvasive procedure and will provide better overall opportunities for organism recovery. Human clinical specimens were examined from 45 patients with confirmed cryptosporidiosis or suspected of having the infection. Tissue biopsy sections, fecal wet preparations, and permanent stained smears were examined. Stool specimens were submitted in 10% Formalin, 2.5% potassium dichromate, and polyvinyl alcohol and were examined for oocysts by using 15 different methods: phase-contrast and light microscopy; Sheather's sugar flotation; Formalin concentration techniques; 10% potassium hydroxide; Giemsa; trichrome; periodic acid-Schiff; modified periodic acid-Schiff; silver methenamine; acridine orange; auramine-rhodamine; Kinyoun acid-fast; Ziehl-Neelsen carbolfuchsin; and a modified acid-fast procedure. Each technique or combination of techniques was assessed by organism quantitation, organism morphology, and ease of visual recognition. Based on these comparative studies, the modified Ziehl-Neelsen carbolfuchsin stain on 10% Formalin-preserved stool is recommended for the recovery and identification of Cryptosporidium.
Genetic probes for enterotoxigenic Escherichia coli isolated from childhood diarrhea in the Central African Republic
Authors: Georges M C , Wachsmuth I K , Birkness K A , Moseley S L , Georges A J
Published: January 2020

Escherichia coli strains were isolated from 778 children with diarrhea and 151 well children in the Central African Republic over a period of 1 year. These 929 strains were assayed for heat-labile and heat-stable enterotoxin production and were hybridized (probed) with structural genes for these enterotoxins. Twenty-four isolates from diarrheal patients and one isolate from a well child were found to be toxigenic by assay and probe. Minor discrepancies were encountered with both assays and probes during initial screening procedures, but the two methodologies were ultimately comparable.
Rapid Indirect Hemagglutination Test for Serotyping
Pasteurella haemolytica
Authors: Fraser J. , Donachie W. , Quirie M. , Gilmour N. J. L.
Published: January 2020

A modified indirect hemagglutination test which enabled
Pasteurella haemolytica
to be serotyped in 3 h is described. There was 100% correlation with the conventional test for both the 15 prototype strains and the 50 field isolates. It was found that nonviable cultures could also be serotyped.
Disk agar diffusion susceptibility testing with 30-micrograms ceftazidime disks: confirmation of interpretive breakpoints and quality control guidelines
Authors: Jones R N , Barry A L , Thornsberry C
Published: January 2020

Ceftazidime is a wide-spectrum, beta-lactamase-stable cephalosporin with remarkable potency against Pseudomonas spp., Enterobacteriaceae, and some gram-positive species. The reevaluation of the 30-micrograms ceftazidime disk diffusion tests with commercially prepared disks confirms the proposed susceptibility breakpoint zone of greater than or equal to 17 mm (minimal inhibitory concentration correlate, less than or equal to 8.0 micrograms/ml) and the resistance breakpoint zone of less than or equal to 13 mm (minimal inhibitory concentration correlate, greater than or equal to 32 micrograms/ml). Major and minor interpretive errors were only 4.4%, and these errors could be further reduced to 1.1% by not testing gram-positive organisms, particularly enterococci and Staphylococcus spp. On the basis of the results from a multilaboratory quality control study, the following zone diameter quality control guidelines are suggested: Escherichia coli ATCC 25922, 27 to 31 mm; Staphylococcus aureus, ATCC 25923, 16 to 20 mm; Pseudomonas aeruginosa ATCC 27853, 24 to 28 mm.
Comparison of a radiometric and a broth-slide system for aerobic blood culture
Authors: Smith J A , Roberts F J , Ngui-Yen J
Published: January 2020

In a comparison of the radiometric BACTEC 460 (Johnston Laboratories) and the BCB broth slide system (Roche Diagnostics Division), the latter yielded a slightly greater number of clinically significant microorganisms, as well as contaminants, from aerobic blood cultures. These differences may reflect the larger volume of blood required for and the greater amount of manipulation associated with the BCB.
Comparison of the Immulok cultureset kit and virus isolation for detection of herpes simplex virus in clinical specimens
Authors: Hayden F G , Sorensen A S , Bateman J A
Published: January 2020

The Immulok test performed at 24 h after inoculation had a 73% sensitivity and 97.5% specificity for detecting herpes simplex virus in clinical specimens, as compared with viral culture in human embryonic lung fibroblasts. The test increased the proportion of positive specimens reportable at 24 h by 48% (P less than 0.01) but failed to detect 4 of 31 (13%) specimens positive for cytopathic effect at 24 h and 13 of 32 (41%) specimens positive at greater than or equal to 48 h after inoculation.
Rapid test for identification of heat-labile enterotoxin-producing Escherichia coli colonies
Authors: Finkelstein R A , Yang Z
Published: January 2020

A latex particle agglutination test is described which is suitable for the recognition of heat-labile enterotoxin-producing colonies of Escherichia coli immediately after primary culture on a variety of commonly used enteric diagnostic media. The test is simple and economical to perform, and the results are available in minutes.
Normalized enzyme-linked immunosorbent assay for determining immunoglobulin G antibodies to cytomegalovirus
Authors: Kiefer D J , Phelps D A , Halbert S P
Published: January 2020

A normalized enzyme-linked immunosorbent assay for the determination of immunoglobulin G antibodies to cytomegalovirus is described. The rapid assay involves three 30-min incubations and permits the quantitation of antibody levels with a single-specimen dilution in conjunction with a reference antibody preparation. The results obtained with the normalized enzyme-linked immunosorbent assay correlated closely with the results of complement fixation titrations and another commercially available enzyme-linked immunosorbent assay. The specificity of the procedure was further demonstrated by viral absorption, using cytomegalovirus from two different sources and other viral antigen preparations, including rubella and influenza. The reproducibility of the normalized test results is good and allows for greater uniformity of reporting on a day-to-day basis, as well as between laboratories.
Serious nosocomial infection caused by Morganella morganii and Proteus mirabilis in a cardiac surgery unit
Authors: Williams E W , Hawkey P M , Penner J L , Senior B W , Barton L J
Published: January 2020

In July and August 1981, five patients in the cardiac surgery unit of the Bristol Royal Infirmary developed septicemia caused by Morganella morganii, Proteus mirabilis, or both of these species. Three of the patients had serious wound infections, and three of the patients died. Typing of the M. morganii isolates by O-serotyping and of the P. mirabilis isolates by O-serotyping, proticine production and sensitivity, and the Dienes reaction confirmed cross infection by both species. Although M. morganii has been regarded as a relatively unimportant human pathogen in the past, it may prove to be an important cause of nosocomial infection in the future.
Infection caused by thymidine-requiring, trimethoprim-resistant bacteria
Authors: King C H , Shlaes D M , Dul M J
Published: January 2020

We first noted the appearance of thymidine-requiring, gram-negative bacilli in clinical specimens 2 years ago. Since then we have seen 10 patients colonized or infected with these organisms. These strains do not grow on Mueller-Hinton media, growth on MacConkey agar is variable, and growth in API 20E (Analytab Products) and Enterobacteriaceae-Plus Cards (AutoMicrobic system; Vitek Systems Inc.) is inadequate for reliable identifications. Thymidine-requiring organisms are routinely resistant to sulfonamides and trimethoprim. Infection or colonization is associated with previous sulfamethoxazole-trimethoprim therapy in most cases. Of 10 patients, 1 had septicemia of urinary tract origin, 5 had urinary tract colonization or infection, 2 had wound colonization, and two had colonization of respiratory secretions. Thymidine-requiring, gram-negative bacilli can be pathogens and present potential problems in diagnosis, identification, and susceptibility testing.
Evaluation of the Prompt inoculation system for preparation of standardized bacterial inocula
Authors: Lund M E , Hawkinson R W
Published: January 2020

Standardized inocula prepared with the 3M Prompt inoculation system were evaluated by (i) performing colony counts on the inocula and (ii) employing these inocula in disk diffusion or broth microdilution susceptibility tests. The inoculation wand delivered 1.85 X 10(8.0) +/- 0.6 log10 CFU to the various diluents tested. Inocula prepared in 1 ml of saline and used to inoculate disk diffusion tests resulted in 96.5% agreement between Prompt and standard tests when Prompt inocula were used within 15 min of preparation and 95.6% agreement between paired tests when Prompt inocula were allowed to sit at room temperature for 2 h before use. With 15-min Prompt inocula, only one (0.04%) major discrepancy between paired tests was observed. The 2-h Prompt inocula gave three (0.13%) major or very major discrepancies. The 15-min Prompt inocula prepared in 30 ml of diluent resulted in 98.2% of Prompt minimal inhibitory concentrations within +/- 1 log2 dilution step of the standard test result, whereas the 2-h inocula resulted in 97.4% agreement between paired minimal inhibitory concentrations at this level. Thus, the Prompt inocula were found to give results equivalent to those obtained from inocula prepared by conventional procedures.
Identification of coagulase-negative staphylococci with the API STAPH-IDENT system
Authors: Almeida R J , Jorgensen J H
Published: January 2020

A group of 300 clinically derived isolates of coagulase-negative staphylococci were tested in parallel with the API STAPH-IDENT system (Analytab Products) and 14 conventional biochemical tests contained in Kloos and Schleifer's simplified scheme for identification of human Staphylococcus species. STAPH-IDENT is a miniaturized biochemical test strip that incorporates four synthetic chromogenic substrates, urea, arginine, and four carbohydrates and that requires only a 5-h test period. Use of the STAPH-IDENT system alone allowed correct or partly correct classification of 67% (201 of 300) of the study isolates. However, if a supplemental test was performed (most often novobiocin susceptibility), correct classification of an additional 25.7% (77) was possible, for a total of 92.7% of isolates identified to the species level. Species correctly identified included 94% (116 of 123) of Staphylococcus epidermidis isolates, 98% (63 of 64) of S. saprophyticus, 71% (34 of 48) of S. hominis, 100% (22) of S. simulans, 100% (18) of S. haemolyticus, 100% (17) of S. warneri, and 100% (8) of S. capitis. Fourteen percent (42 of 300) of profile codes encountered in this study were not included in the STAPH-IDENT profile register, but were included in Analytab Products' expanded computer data base.
Determination of herpes simplex virus type-specific antibodies by enzyme-linked immunosorbent assay
Authors: Coleman R M , Pereira L , Bailey P D , Dondero D , Wickliffe C , Nahmias A J
Published: January 2020

We determined type-specific antibodies to herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) by an indirect enzyme-linked immunosorbent assay, using as antigens HSV-1 glycoprotein gC-1 and a HSV-2-specific polypeptide purified on affinity columns of monoclonal antibodies. All sera were initially screened for HSV antibodies by the enzyme-linked immunosorbent assay with a pool of Triton X-100-extracted antigens of HSV-1- and HSV-2-infected HEp-2 cells. The titer of HSV antibodies was predicted from a linear regression curve based on the absorbance of the initial 1:50 serum dilution. The sensitivity and specificity of the screening assay and of the assay for type-specific antibodies were established.
Capsular and somatic serotypes of Pasteurella multocida isolates recovered from healthy and diseased rabbits in Texas
Authors: Lu Y S , Pakes S P , Stefanu C
Published: January 2020

A total of 111 Pasteurella multocida isolates recovered from healthy and diseased rabbits were typed for capsular and somatic antigens by the typing systems of Carter and Heddleston, respectively. The major serotypes of the 48 P. multocida isolates recovered from nasal cavities of healthy rabbits were serotypes 12:A (33%), nontypable:A (50%), and nontypable:D (10%). Similarly, the major serotypes of the 63 P. multocida isolates obtained from rabbits with rhinitis, pneumonia, conjunctivitis, tympanitis, or cutaneous abscesses were serotypes 12:A (32%), nontypable:A (30%), and 3:A (16%). Serotype 12:A was predominant, regardless of whether the isolates were recovered from healthy or diseased rabbits.
Microassay for Sindbis virus and interferon activity
Authors: Lloyd R E , Weigent D A , Stanton G J
Published: January 2020

A simple and rapid microplaque assay for Sindbis virus was developed which uses microtiter plates and overlay medium consisting of methylcellulose and specific antibody to Sindbis virus. Discrete plaque formation was consistently observed on baby hamster kidney (BHK-15) cells within 24 h. The assay was reproducible, quantitative, and had about the same sensitivity as the agar overlay technique on chicken embryo cells in 35-mm petri dishes. The microplaque assay could be accurately applied to measuring interferon activity, particularly at low interferon levels. Overall, the microassay methods described here for assay of Sindbis virus yields and interferon activity retain the accuracy of chicken cell macroplaque assays while offering greater simplicity, rapidity, and economy of materials. This assay is also potentially applicable for use with other togaviruses.
Comparative recovery of bacteria and yeasts from lysis-centrifugation and a conventional blood culture system
Authors: Kiehn T E , Wong B , Edwards F F , Armstrong D
Published: January 2020

Blood cultures obtained with a lysis-centrifugation (L-C) system and a conventional two-bottle broth system were compared for the recovery of bacteria and yeasts from 7,000 cultures. The L-C system recovered significantly more total organisms, Escherichia coli, and Candida spp. and detected more patients with bacteremia and fungemia due to members of the family Enterobacteriaceae and yeasts. The broth system recovered significantly more streptococci and detected significantly more low-level Pseudomonas bacteremias. Polymicrobic bacteremia and fungemia were detected equally well by either culture system. Aerobic organisms grew equally well on blood, chocolate, or brain heart infusion agar plates used for L-C inoculation. A total of 82% of colony counts measured no more than 10 CFU/ml of blood, and it was at these low levels that enhanced detection of organisms by either system was observed. The L-C system isolated organisms and detected yeasts more rapidly than did the broth system. Contaminants occurred in 8.2% of L-C cultures and 1.9% of broth cultures. Low colony counts on L-C plates occurred for both Staphylococcus epidermidis contamination and septicemia.
Failure of preexisting antibody against hepatitis B surface antigen to prevent subsequent hepatitis B infection
Authors: Swenson P D , Escobar M R , Carithers R L , Sobieski T J
Published: January 2020

We studied a patient who developed acute hepatitis B virus (HBV) infection despite the presence of preexisting antibody to the surface antigen of HBV (anti-HBs). Anti-HBs has been reported to consist primarily of antibody against the common a determinant of HBV. Antibody directed against this major determinant appears to confer protection against HBV, regardless of the subtype. Our patient was shown to have had preexisting anti-HBs of anti-d but not anti-a specificity. She subsequently developed non-A, non-B viral hepatitis followed by an episode of acute hepatitis B after exposure to HBV of the ayw subtype.
Rocky Mountain spotted fever vaccine in an animal model
Authors: Folds J D , Walker D H , Hegarty B C , Banasiak D , Lange J V
Published: January 2020

Formalin-killed, purified Rickettsia rickettsii vaccine was evaluated in a guinea pig model of R. rickettsii infection. Vaccinated guinea pigs were partially protected by the vaccine when challenged with virulent, viable rickettsiae. Greater protection was observed when higher doses of vaccine were given and when frequent booster injections were administered. Stimulation of cell-mediated immunity to the vaccine antigens was variable and also appeared to be achieved more reproducibly with booster vaccinations. Serum antibody was elicited by high doses of vaccine and by booster vaccinations. The presence of serum antibody was useful in predicting immunity to challenge with R. rickettsii.
Direct micromethod for diagnosis of acute and congenital Chagas' disease
Authors: Feilij H , Muller L , Gonzalez Cappa S M
Published: January 2020

A microhematocrit concentration method (MH) for immediate diagnosis of Chagas' disease during the acute stage or in congenital cases was standardized. Parasitemia as low as 1,000 parasites per ml was detected, after centrifugation of six 50-microliters capillary tubes, by 10-min microscopic observation of each buffy coat spread between slide and cover glass. Operator's time was reduced by at least one-third when compared with a fresh blood observation (FB). In 12 of the 15 patients studied, diagnosis was performed in 4.9 +/- 3.08 min with MH, whereas 27.0 +/- 12.1 min were necessary when FB was used. In the three remaining patients whose FB results were negative, MH became positive after 13, 16, and 40 min. In our experience, FB proved to be more sensitive than previously reported. Suckling mouse inoculation also proved to be sensitive but, as in xenodiagnosis and in hemoculture, the delay in getting the final result was a limiting factor.
Antigenic relationships among some bovine rotaviruses: serum neutralization and cross-protection in gnotobiotic calves
Authors: Woode G N , Kelso N E , Simpson T F , Gaul S K , Evans L E , Babiuk L
Published: January 2020

A method was further developed to screen non-tissue-culture-adapted bovine rotaviruses for serotype, using a neutralization test with infectious fecal rotavirus. One of those rotaviruses (B223) which was not blocked by antiserum to the neonatal calf diarrhea virus (NCDV) serotype was then adapted to cell culture in the presence of the antiserum for two or more passages and hyperimmune antiserum to this isolate had a 60-fold-higher homologous neutralization titer than with the NCDV serotype rotavirus. Seventy-three isolates were serotyped and eight (11%) were not of the NCDV serotype (bovine rotavirus serotype I). Of these eight, five belonged to the new bovine rotavirus serotype II and three were not typed, indicating the existence of one or more further serotypes. Cross-protection studies in gnotobiotic calves showed that cross-protection only occurred between rotaviruses of the same serotype, and even a minor serotype difference was sufficient for the calves to show a lack of cross-protection. The serotypes (I and II and the three untyped isolates) also showed differences in the rate of migration in polyacrylamide gel electrophoresis of some of their RNA segments (no. 4, 6, 7, 8, 9, 10), indicating that they were of different electropherotypes.
Quantitative screening of clinical isolates for immunoglobulin A protease production
Authors: Lindler L E , Stutzenberger F J
Published: January 2020

The production of immunoglobulin A (IgA) protease is a potentially useful marker in differentiating pathogenic from nonpathogenic species of clinical isolates; however, current quantitative assay methods are too tedious for routine application. A simple quantitative method was developed to screen clinical isolates for IgA protease production. This method is based on the specificity of reaction between IgA and alpha chain-specific antiserum in an immunochemistry analyzer (Beckman Instruments, Inc., Brea, Calif.). Colonies of IgA protease producers (Streptococcus sanguis, Streptococcus pneumoniae, Neisseria gonorrhoeae, Neisseria meningitidis, and Haemophilus influenzae) were picked from solid media, transferred to brain heart infusion containing IgA1, and incubated at 37 degrees C for at least 2 h to provide a detectable decrease in IgA concentration. The standard deviation for randomly picked colonies within a species was about +/- 15%. Several IgA protease-negative species caused no detectable reduction in the IgA content of the system. The specificity of the IgA measurement eliminates the requirements for extensive purification and radiolabeling of substrate and provides the basis for a well-defined IgA protease activity unit (micrograms of IgA1 cleaved per minute per milliliter of culture).
Toxic shock syndrome: modification and comparison of methods for detecting marker proteins in Staphylococcus aureus
Authors: Cohen M L , Graves L M , Hayes P S , Gibson R J , Rasheed J K , Feeley J C
Published: January 2020

Development of a new medium and modification of incubation conditions increased production of toxic shock syndrome marker proteins and enabled detection of small volumes of pyrogenic exotoxin C (PEC) by isoelectric focusing and staphylococcal enterotoxin F (SEF) by a newly developed solid-phase radioimmunoassay. The results were compared with those obtained with previously described methods. The results were identical, and all PEC-positive isolates were SEF positive. In a second study of 262 randomly selected Staphylococcus aureus isolates examined by isoelectric focusing and solid-phase radioimmunoassay but grown in fresh beef heart medium, 47 (17.9%) isolates were PEC and SEF positive; however, 9 (3.4%) were PEC positive and SEF negative, and 3 (1.1%) were SEF positive and PEC negative. When grown in buffered beef heart yeast extract medium, six of the previously PEC-positive and SEF-negative isolates were PEC negative. Autoradiographic analysis of selected isolates demonstrated that PEC- and SEF-positive strains bound SEF antitoxin to the protein at isoelectric point 7.2, suggesting that in staphylococci from patients with toxic shock syndrome, PEC and SEF are the same protein. In screening staphylococci for toxic shock syndrome marker proteins, isoelectric focusing to identify PEC may detect false-positive proteins and may be more susceptible to technical variation than immunological methods to detect SEF.
Comparison of a radiometric method (BACTEC) and conventional culture media for recovery of mycobacteria from smear-negative specimens
Authors: Morgan M A , Horstmeier C D , DeYoung D R , Roberts G D
Published: January 2020

The BACTEC system and three conventional media (Middlebrook 7H10, selective Middlebrook 7H11 [S7H11], and Lowenstein-Jensen [LJ] were compared for their mean recovery times and recovery rates of mycobacteria from acid-fast, smear-negative clinical specimens. Of the 71 smear-negative, culture-positive specimens recovered from 2,165 submitted smear-negative cultures, the BACTEC system detected 71.8%, compared with 88.7% for the conventional three-medium system. When media were individually compared, BACTEC medium (Middlebrook 7H12) was more successful in recovering mycobacteria (71.8%) than was LJ (62%), Middlebrook medium 7H10 (55.9%), or Middlebrook S7H11 medium (52.1%). Middlebrook 7H11 medium containing sodium selenate was also evaluated and did not increase the recovery rate or decrease the recovery time of mycobacterial species when compared with LJ, Middlebrook 7H10, S7H11, and 7H12 media. The mean detection time for the BACTEC system was less than that by conventional methods for the seven species of mycobacteria recovered. Detection times for Mycobacterium tuberculosis on the BACTEC system and conventional cultural systems were 13.7 and 26.3 days, respectively.
In vitro response of Staphylococcus aureus from cystic fibrosis patients to combinations of linoleic and oleic acids added to nutrient medium
Authors: Campbell I M , Crozier D N , Pawagi A B , Buivids I A
Published: January 2020

The effect of supplementing nutrient substrate with various combinations of concentrations of oleic and linoleic acids on the growth of 11 strains of Staphylococcus aureus was assessed. Whereas increasing the concentration of linoleic acid by itself greatly diminished the growth of all 11 strains, concomitant increases in oleic acid greatly diminished the inhibitory effect of linoleic acid. With oleic acid in the nutrient substrate, most of the strains were induced to produce slime which surrounded the cells. Since the slime incorporated oleic but not linoleic acid, such slime production isolated the cells from direct contact with the growth inhibitor, linoleic acid.
Development of an immunofluorescence focus assay for Ebola virus
Authors: Truant A L , Regnery R L , Kiley M P
Published: January 2020

A 48-h indirect immunofluorescence focus assay for the quantitation of Ebola virus was developed, utilizing HeLa-229 cell monolayers. The dose dependency and the sensitivity of this assay as compared with conventional assays are reported. This indirect immunofluorescence focus assay can be used as a rapid, quantitative test for the detection of Ebola virus, an agent from Africa known to cause hemorrhagic fever.
Electron microscopy of the coccoid form of Campylobacter jejuni
Authors: Buck G E , Parshall K A , Davis C P
Published: January 2020

Confluent cultures of Campylobacter jejuni incubated for 24 and 48 h each were examined by electron microscopy. Although the 24-h-old cells exhibited typical curved morphology, the 48-h-old cells showed rounded morphology with a loss of cell integrity. This appeared to be an autolytic process that occurred very rapidly after the culture became mature. These results confirm previous evidence that the coccoid form of this organism is a degenerate state.
Direct isolation of H1N2 recombinant virus from a throat swab of a patient simultaneously infected with H1N1 and H3N2 influenza A viruses
Authors: Nishikawa F , Sugiyama T
Published: January 2020

Two H1N2 recombinant viruses were isolated by a plaquing method from a throat swab of a patient who was simultaneously infected with H1N1 and H3N2 influenza viruses during the Tokyo epidemic of 1981. This is the first direct evidence that recombination of influenza viruses occurred in the human body.
Immune response to Bacteroides ureolyticus in a patient with brain abscess
Authors: Lalitha M K , Mathai K V , Koshi G
Published: January 2020

A high titer (1:256) of agglutinating antibodies against Bacteroides ureolyticus was demonstrated in a 35-year-old woman with brain abscess, using a microagglutination test. Tests done with B. ureolyticus and heterologous sera as well as with heterologous strains and the patient's serum were negative. Circulating antibody to B. ureolyticus has not been reported previously.
Fatal septicemia due to amphotericin B-resistant Candida lusitaniae
Authors: Guinet R , Chanas J , Goullier A , Bonnefoy G , Ambroise-Thomas P
Published: January 2020

Five yeast strains, causally associated with septicemia and death in a patient after peritonitis, were identified as Candida lusitaniae van Uden et do Carmo-Sousa by standard methods. The organism was initially susceptible to 5-fluorocytosine but strongly resistant to amphotericin B, requiring 50 micrograms/ml for complete inhibition at 48 h.
Evaluation of the BACTEC antimicrobial removal system for detection of bacteremia
Authors: McGuire N M , Kauffman C A , Hertz C S , Kovach J M
Published: January 2020

The BACTEC 16B resin medium was developed to detect bacteremia in patients receiving antimicrobial therapy. Over a 9-month period, we compared the efficacy of the BACTEC 16B bottle to the conventional aerobic BACTEC 6B bottle. Of a total of 1,524 sets of blood cultures, 79 yielded presumed pathogens. Of these 79 sets, 42 (53.2%) were positive in both the 16B and 6B bottles, 23 (29.1%) were positive only in the 16B bottle, and 14 (17.7%) were positive only in the 6B bottle. For patients receiving antimicrobial drugs, 33 of 34 (97.1%) sets were positive for pathogens in the 16B bottle, but only 15 of 34 (44.1%) were positive in the 6B bottle. In 19 (55.9%) of the 34 sets, only the 16B bottle yielded growth. The resin bottle was more useful for patients with gram-positive bacteremia than for those with gram-negative bacteremia. The BACTEC 16B resin medium increases the recovery of organisms from bacteremic patients receiving antimicrobial agents and should be used in addition to the standard BACTEC aerobic bottle for such patients.
Isolation and characterization of flagellar preparations from Pseudomonas species
Authors: Montie T C , Stover G B
Published: January 2020

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis has been used previously to characterize the flagellin of Pseudomonas aeruginosa. flFlagella from several other clinically important species of pseudomonads have been characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their molecular weights have been found to vary among species as follows: P. maltophilia B69 Fla, 33,000; P. stutzeri HEW, 55,000; P. aeruginosa M-2, 53,000. The flagella of P. cepacia strains were divided into two groups based on molecular weight. Type I had a molecular weight of 31,000. The molecular weight of type II was in the range of 44,000 to 46,000. Serologically, type I is a homologous group, whereas type II is a heterologous group. The two flagellin types of P. cepacia appear to be analogous to the two major flagellin types of P. aeruginosa. Characterization of P. cepacia strains by flagellin types may serve as a molecular epidemiological tool.
Serodiagnosis of infectious mononucleosis with a bovine erythrocyte glycoprotein
Authors: Fletcher M A , Klimas N G , Latif Z A , Caldwell K E
Published: January 2020

A glycoprotein from bovine erythrocyte membrane was evaluated in two immunoassays as a reagent for the serodiagnosis of infectious mononucleosis (IM). We previously reported that a partially purified preparation of this glycoprotein, when attached to latex beads, agglutinated in the presence of IM heterophile antibody. In the present study, we used a highly purified form of the glycoprotein both as an agglutinating reagent, covalently bound to latex, and in a solid-phase sandwich-type radioimmunoassay (RIA) for IM antibody detection in a larger population of patients. We tested serum samples from college students with symptoms suggestive of IM with the latex reagent (143 samples) and with the RIA (245 samples). Correlation of these two tests, both with each other and with the classical differentially absorbed, agglutination tests for Paul-Bunnell antibody in IM sera, using fresh sheep or horse cells, was excellent (greater than 97% agreement). The new tests also corresponded in most cases with a rapid, unabsorbed preserved horse erythrocyte slide test. However, in this study of 245 samples, both apparent false-positives (5 samples) and apparent false-negatives (3 samples) were observed with this slide test. In conclusion, we found that the bovine glycoprotein as a reagent can facilitate the diagnosis of IM, giving results comparable to those with erythrocyte agglutination tests on differentially absorbed sera. The advantages are ease and speed of performance (latex test), potential for automation (RIA test), stability and uniformity of the glycoprotein reagent (latex and RIA tests), and most importantly, the ability to use unabsorbed sera (latex and RIA tests).
Inactivation of contraceptive steroid hormones by human intestinal clostridia
Authors: Bokkenheuser V D , Winter J , Cohen B I , O'Rourke S , Mosbach E H
Published: January 2020

Steroid hormones reduced in ring-A are devoid of hormonal activity. In metabolic experiments we found that human fecal flora reduced the delta 4-3-keto structure of natural progestins to 3 alpha-hydroxy, 5 beta-steroid metabolites (3 alpha,5 beta) and of synthetic progestins to a mixture of 3 alpha,5 beta and 3 beta,5 beta compounds. 3 alpha,5 beta-Reductase was synthesized by Clostridium paraputrificum and had a strong affinity for natural progestins such as progesterone. 3 beta,5 beta-Reductase was synthesized by Clostridium innoculin and had a stronger affinity for synthetic progestins. A third enzyme, 3 beta,5 alpha-reductase, was synthesized by St. Luke's strain 209 (Clostridium species "J-1") but was only observed when pure cultures were used. Ring-A reduction of synthetic progestins was 3 to 10 times slower than that of natural progestins, thus explaining the pharmacological superiority of synthetic progestins over naturally occurring analogs.
Rapid detection of bacterial growth in blood cultures by bioluminescent assay of bacterial ATP
Authors: Molin O , Nilsson L , Anséhn S
Published: January 2020

A method for rapid detection of bacterial growth in blood cultures by bioluminescent assay of bacterial ATP was developed. Samples from blood cultures were treated with a blood-lysing detergent combined with an ATP-hydrolyzing enzyme to destroy blood cell ATP. Blood cell ATP which was bound to cell debris and escaped the ATPase activity was then separated from the bacteria on Percoll density gradients. Bacterial ATP from the bacterial layer was determined by the firefly bioluminescence system. In simulated blood cultures inoculated with 10 CFU of bacteria per ml of blood, bacterial ATP levels exceeded the detection limit (10(-10) M) after 6 to 10 h of incubation. This ATP level corresponds to approximately 10(4) CFU of bacteria per ml.
Elimination of multiple reactions of the Phadebact Streptococcus coagglutination test
Authors: Jones D E , Kanarek K S , Angel J L , Lim D V
Published: January 2020

Strong multiple reactions often occur with the Phadebact Streptococcus test when the culture contains blood. These reactions interfere with the identification of the Lancefield groups of streptococci. Group B streptococci from the vagina of pregnant women are difficult to identify by slide coagglutination because of the frequent presence of blood on culture swabs. Elimination of these multiple reactions caused by blood would permit rapid identification of group B streptococci in pregnant women. Vaginal broth cultures were examined to determine the cause of multiple reactions with slide coagglutination and to eliminate them from the testing procedure. Of 245 maternal broth cultures, 135 (55%) yielded multiple reactions when tested by coagglutination. Such reactions were either eliminated or greatly diminished by heating the broth sample to 90 degrees C for 10 min. It was also found that globulins in the serum may be responsible for multiple reactions with blood. This heating protocol will permit vaginal broth cultures to be rapidly tested for group B streptococci by slide coagglutination.
Inactivation of hepatitis B virus by intermediate-to-high-level disinfectant chemicals
Authors: Bond W W , Favero M S , Petersen N J , Ebert J W
Published: January 2020

In five separate tests, hepatitis B virus in dried human plasma was exposed for 10 min at 20 degrees C to disinfectant chemicals having activity levels ranging from intermediate (e.g., 70% isopropyl alcohol) to high (e.g., 2% aqueous glutaraldehyde at pH 8.6). Five chimpanzees (one animal per disinfectant chemical) received treated material intravenously, and none showed signs of infection after post-inoculation periods of 9 months. Two animals were rechallenged with inoculum treated in the same manner, except that saline was used instead of a disinfectant chemical; both were infected within 4 weeks. Our results showed that hepatitis B virus was not as resistant to disinfectant chemicals as once thought and suggested that chemicals with similar activity levels (intermediate to high) might possibly be used on hepatitis B virus contamination with a margin of safety.
Comparison of outer membrane protein subtypes of Haemophilus influenzae type b isolates from healthy children in the general population and from diseased patients
Authors: Hampton C M , Barenkamp S J , Granoff D M
Published: January 2020

Over a 12-month period we obtained throat cultures from 1,448 children less than 5 years of age attending well-child clinics and identified 24 carriers of Haemophilus influenzae type b (1.7%). The outer membrane protein subtypes of the strains from the carriers were compared to the subtypes of isolates from 50 patients with Haemophilus type b disease hospitalized in St. Louis, Mo., during the same period (1981 to 1982), and the latter were compared to the subtypes of isolates from 51 patients hospitalized between 1977 and 1980. There were no significant differences in the frequencies of the five most common subtypes (1L, 1H, 2L, 2H, and 3L), comparing isolates from the carriers to those from the patients. However, 5 of the 24 throat isolates had the unusual 13L subtype compared with only 1 of the 50 invasive isolates (P = 0.02). The lower frequency of 13L strains among the invasive isolates suggests that type b isolates with this subtype may be less pathogenic than type b isolates with other subtypes. Subtype 2L strains accounted for only 2% of recent cerebrospinal fluid or blood isolates, compared with 22% of those from 1977 to 1980 (P = 0.02). Subtype 1H and 3L strains together accounted for 73%, compared with 47% of the earlier ones (P = 0.02). Thus, temporal shifts may also occur in the subtype distribution of Haemophilus type b strains causing invasive disease in a community.
Evaluation of screening tests for the detection of antistreptolysin O antibodies
Authors: Lue Y A , Nicolas C , Kemawikasit P , Pierre A , McLean T I , Simms D H
Published: January 2020

The accuracy of two screening tests, one utilizing serum and the other utilizing whole blood, was compared with the accuracy of the conventional macrotitration method for the detection of antistreptolysin O antibodies. Of the 569 specimens tested with the serum screening procedure and the macrotitration method, 235 and 282, respectively, were positive for antistreptolysin O antibodies. Comparative testing of 200 specimens with the peripheral blood screening test and the macrotitration method gave 60.5% by the macrotitration procedure. Discrepant results with both procedures were obtained with specimens having 166 Todd units. The results suggest that these screening procedures can be used to screen specimens for the presence of significant antistreptolysin O antibodies.
Sensitive radioimmune assay for measuring Aleutian disease virus antigen and antibody
Authors: Aasted B , Bloom M E
Published: January 2020

A solid-phase, one-step radioimmune assay was developed which could detect as little as 0.02 microliter of a standard Aleutian disease virus antigen preparation, approximately 3.2 ng of viral protein. Virus antigen was measured in different mink organs and cell types during experimental intraperitoneal infection. The gut and kidney were the first organs in which virus antigen could be detected (day 3 to 6 after infection). On day 6 or later virus antigen was found in spleen, liver, kidney, lymph nodes, peritoneal exudate, and bone marrow cells. With inhibition of antigen binding, a radioimmune assay was developed for antibody detection. Viral antibodies could be detected as early as 3 days after infection. Antibody titers from 1/10(5) to more than 1/10(6) were found in plasmacytotic mink. When the sensitivity of the antibody radioimmune assay was compared with that of other known methods for anti-Aleutian disease virus quantitation, the radioimmune assay was considerably more sensitive, detecting as little as 5 ng of antibody.
Influence of inoculum growth phase on microdilution susceptibility tests
Authors: Barry A L , Badal R E , Hawkinson R W
Published: January 2020

Two types of commercially available microdilution trays were inoculated with log-phase cultures, stationary-phase cultures, and direct suspensions of 18- to 24-h colonies, with essentially comparable results. Direct pick-up of colonies was also tested with two Prompt inoculation systems (3M Co.); they were found to be convenient and reliable methods for standardizing inocula without preincubation in broth and without turbidity adjustment.