bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzyme immunoassays in which biotinillated beta-lactamase is used for the detection of microbial antigens
Authors: Yolken R H , Wee S B
Published: January 2020

The performance characteristics of enzyme immunoassays are determined to a great extent by the enzyme-substrate system utilized for the immunoassay. Beta-lactamases (penicillin amido-beta-lactamhydrolase EC 3.5.2.6) offer a number of advantages which might make them useful in immunoassay systems. We linked beta-lactamase from Bacillus cereus with biotin and used the biotinillated enzyme to devise immunoassay systems for the detection of a number of microbial antigens. An assay system in which antibodies to the polyribitol phosphate antigen of Haemophilus influenzae type b were used was capable of detecting between 0.4 and 1.6 ng of that antigen. Similarly, an assay in which antibodies to the common antigens of adenoviruses and biotin-linked beta-lactamase were used was capable of detecting between 1 and 10 50% tissue culture infective doses of a strain of enteric-type adenovirus. When applied to the detection of rotavirus, a similar system in which biotinillated beta-lactamase was used was capable of detecting small amounts of antigen in a standard rotavirus preparation. This assay could also detect virus in 36 of 37 stool specimens from children with rotavirus gastroenteritis. The positive specimens could easily be distinguished from negative ones by the naked eye, and a permanent record of the qualitative results could be obtained by the use of a standard office photocopying machine. Beta-lactamases have promise for use in practical enzyme immunoassay systems, especially in situations in which expensive colorimetric instrumentation is not available.
Diagnostic value of interactions between members of the family Neisseriaceae and lectins
Authors: Doyle R J , Nedjat-Haiem F , Keller K F , Frasch C E
Published: January 2020

The lectin slide agglutination test for Neisseria gonorrhoeae has been modified and improved. Results show that wheat germ agglutinin and soybean lectin agglutinate 100% (193 of 193 tested) of clinical isolates of N. gonorrhoeae. Lectin-reactive meningococci can be readily identified by the hydrolysis of gamma-glutamyl-beta-naphthylamide. Branhamella catarrhalis, Neisseria lactamica, Neisseria sicca, Neisseria subflava, Neisseria perflava, and meningococcal serogroups A, B, C, X, Y, and Z do not interfere with the positive identification of N. gonorrhoeae. The frequently encountered problem of autoagglutination of members of the family Neisseriaceae may be circumvented by a short treatment of cellular suspensions with DNase. Based on agglutination assays, the enzyme treatment did not result in a loss of wheat germ agglutinin receptors from the bacteria. The lectin agglutination test, coupled with the gamma-glutamyl aminopeptidase assay, is proposed as a rapid and accurate means of identifying clinical isolates of gonococci.
Monoclonal antibody capture enzyme-linked immunosorbent assay for detection of bovine enteric coronavirus
Authors: Crouch C F , Raybould T J , Acres S D
Published: January 2020

Monoclonal antibodies reactive with three different viral polypeptides were evaluated singly and in combination as the capture antibody(s) in an enzyme-linked immunosorbent assay system for the detection of bovine enteric coronavirus. Similar levels of sensitivity were found for all combinations tested. A sensitive, highly specific, and reproducible assay for the detection of bovine enteric coronavirus was developed, using a mixture of two of these monoclonal antibodies reactive with antigenic components either external or internal to the virion. These monoclonal antibodies were bound indirectly to 96-well plates via rabbit anti-mouse immunoglobulin. After sample application and incubation, virus was detected by using rabbit anti-coronavirus peroxidase conjugate followed by enzyme substrate and chromagen. Fecal samples from a single herd of cows were screened for the presence of coronavirus by this assay. Five percent of clinically normal cows were found to be shedding coronavirus.
Epidemiological investigation of exfoliative toxin-producing Staphylococcus aureus strains in hospitalized patients
Authors: Piemont Y , Rasoamananjara D , Fouace J M , Bruce T
Published: January 2020

The incidence of exfoliative toxin-producing strains of Staphylococcus aureus was studied. Samples from hospitalized patients of all ages and samples from infants less than 6 weeks old were screened; out of 2,632 coagulase-positive S. aureus strains tested, 6.2% synthesized exfoliative toxin. The clinical features could be assessed in 86 patients harboring exfoliative toxin-producing staphylococci. Skin lesions (pustules, blisters, and bullous impetigo) could be observed only when the exfoliative toxin-positive strains were isolated from the skin. Phage nongroup II strains seemed less skin pathogenic than phage group II strains. Outbreaks and sporadic cases were observed.
Protective efficacies of live attenuated and formaldehyde-inactivated Venezuelan equine encephalitis virus vaccines against aerosol challenge in hamsters
Authors: Jahrling P B , Stephenson E H
Published: January 2020

Although two investigational vaccines are used to immunize humans against Venezuelan equine encephalomyelitis virus, neither had previously been tested for protective efficacy against aerosol exposure. Live attenuated vaccine (TC-83) protected all hamsters challenged by either aerosol or subcutaneous routes with 4.7 to 5.2 log10 PFU of virulent Venezuelan equine encephalomyelitis virus. Formaldehyde-inactivated vaccine (C-84) failed to protect against aerosol challenge but did protect against subcutaneous challenge. Protection elicited by TC-83 vaccine did not depend solely on serum-neutralizing antibody. These studies suggest that TC-83 vaccine is preferable to C-84 vaccine for protecting laboratory workers at risk to aerosol exposure.
Comparative efficacy of liquid enrichment medium for isolation of Campylobacter jejuni
Authors: Hodge D S , Terro R
Published: January 2020

Isolation of Campylobacter jejuni from 1,249 human fecal specimens by direct inoculation on selective Columbia agar and liquid enrichment medium was compared. The use of liquid enrichment medium provided a 30% higher isolation rate of C. jejuni. The overall isolation rate achieved by using direct plating and enrichment together was 8.2%.
Reactivity of Dade rapid plasma reagin card test with low-titer sera
Authors: Fischer G S , Kleger B , Colavita M T
Published: January 2020

Of 105 sera having reagin titers of 1 dilution as determined by the rapid plasma reagin 18-mm circle card test (Hynson, Westcott and Dunning, Baltimore, Md.), 103 (98.1%) were reactive with the Dade rapid plasma reagin card test (Biokit Laboratories, Barcelona, Spain), indicating that the two procedures are comparable in their ability to detect low levels of nontreponemal syphilitic antibody, or reagin.
Detection of enteroviruses by spot hybridization
Authors: Hyypiä T , Stålhandske P , Vainionpää R , Pettersson U
Published: January 2020

A cloned partial cDNA copy of the coxsackievirus B3 genome was used for detecting enteroviruses in infected cells by employing a nucleic acid hybridization procedure. Cells infected with coxsackieviruses A and B, echovirus, and poliovirus gave positive hybridization signals, whereas cells infected with nonrelated viruses did not.
Human rotavirus detection by counterimmunoelectrophoresis versus enzyme immunoassay and electron microscopy after direct ultracentrifugation
Authors: Hammond G W , Ahluwalia G S , Klisko B , Hazelton P R
Published: January 2020

The sensitivity of the counterimmunoelectrophoresis test with NCDV, Wa, and SA-11 rotavirus antisera was 60, 60, and 67%, respectively. The counterimmunoelectrophoresis specificity was greater than 99%, but the low sensitivity is a limiting feature of this test as a first-line immunodiagnostic test for rotavirus detection.
Estimation of rotavirus immunoglobulin G antibodies in human serum samples by enzyme-linked immunosorbent assay: expression of results as units derived from a standard curve
Authors: Bishop R F , Cipriani E , Lund J S , Barnes G L , Hosking C S
Published: January 2020

A method for estimating rotavirus immunoglobulin G (IgG) antibodies by assay of human serum samples at a single serum dilution was studied. Antibody was measured by enzyme-linked immunosorbent assay (ELISA). The optical density of the reaction with a 1:100 dilution of each serum was expressed as ELISA units of antirotavirus IgG by reference to a standard curve. This standard curve was obtained by incorporation in each assay of five dilutions of a serum containing an arbitrary number of units of antirotavirus IgG. Test serum samples found to contain high amounts of antirotavirus IgG were reassayed at a 1:1,000 dilution. There was good correlation between antirotavirus IgG ELISA units in 45 serum samples and endpoint titers of the same samples (Spearman rank correlation coefficient rs, 0.95). Seroconversion during rotavirus infection was defined as an increase in antirotavirus IgG ELISA units per milliliter of greater than 28% (2 X intra-run coefficient of variation of the assay) in consecutive serum samples from the same child. Paired serum samples from nine children with diarrhea not due to rotavirus infection showed no seroconversions. Paired samples from eight children with rotavirus infection showed seroconversions. Estimation of antirotavirus IgG ELISA units in serum is simple, rapid, reproducible, and economical of serum samples. Standardization of results could be achieved by worldwide distribution of a standard serum. Its use would facilitate epidemiological surveys to evaluate potential rotavirus vaccines.
Fluorescent staining of intracellular and extracellular bacteria in blood
Authors: Mansour J D , Schram J L , Schulte T H
Published: January 2020

The fluorescent dye ethidium bromide stains Escherichia coli and Staphylococcus aureus in whole blood. The staining is rapid, relatively specific, and does not require fixation of the sample. Furthermore, stained bacteria can be seen microscopically without the need for a final wash to remove unbound dye. By using lysostaphin, an S. aureus-specific lytic enzyme, we have demonstrated that S. aureus can be stained with ethidium bromide even after phagocytosis. After short periods of incubation with the dye (less than 5 min), bacteria, both intracellular and extracellular, were the predominant fluorescent particles. With increasing time of incubation, blood cell components, notably leukocyte nuclei, began to fluoresce.
Evaluation of the automicrobic system for detection of resistance of Staphylococcus aureus to methicillin
Authors: Woolfrey B F , Lally R T , Ederer M N
Published: January 2020

The AutoMicrobic system (AMS) (Vitek System, Inc., Hazelwood, Mo.) was tested for its ability to determine oxacillin and gentamicin susceptibility of 98 known oxacillin-susceptible and 103 known oxacillin-resistant Staphylococcus aureus isolates. AMS and reference oxacillin susceptibility results were in agreement for all 95 (100%) oxacillin-susceptible isolates. In contrast, only 23 (22.3%) of the 103 known oxacillin-resistant isolates were correctly reported. For the known oxacillin-resistant isolates, 65 received AMS reports at 3 to 4 h, with only 9% being correct, whereas 38 were reported at 5 to 6 h, with 47% being correct. The reliability of AMS gentamicin susceptibility results was evaluated by testing the 198 S. aureus isolates in parallel with MIC-2000 broth dilution tests. AMS gentamicin susceptibility results were found to be reliable and essentially identical to MIC-2000 results. The possibility of improving AMS oxacillin resistance detection by using gentamicin resistance as a linked screening marker for oxacillin resistance was evaluated with data from the parallel AMS and MIC-2000 gentamicin susceptibility tests and from data accrued on recent clinical laboratory isolates. By these two approaches, respective sensitivities of 97 and 99.8%, and specificity of 72%, were found for detection of oxacillin-resistant isolates by using gentamicin resistance as a marker.
Comparison of a new enzyme-linked immunosorbent assay method with counterimmunoelectrophoresis for detection of teichoic acid antibodies in sera from patients with Staphylococcus aureus infections
Authors: Herzog C , Wood H C , Noel I , Booth J C
Published: January 2020

Ribitol-teichoic acid antibodies were measured by a new enzyme-linked immunosorbent assay (ELISA) and by counterimmunoelectrophoresis in serum samples from 47 patients with serious Staphylococcus aureus infections, 63 infected patients, and 177 healthy controls. The same antigen was used for both tests. The group of patients with S. aureus endocarditis (6 patients) had significantly higher ELISA readings than the patients with other deep-seated infections (26 patients) or with an uncomplicated S. aureus bacteremia (15 patients). The patients with other serious gram-positive (40 patients) or gram-negative (23 patients) infections did not differ from the healthy control group. There were only three (7.5%) low-level cross-reactions among the infections caused by gram-positive organisms other than S. aureus. Of 46 initially ribitol-teichoic acid antibody-negative patients followed up for 2 weeks or more, only those developing a serious S. aureus infection showed a significant rise of the ELISA reading. There was a good correlation between ELISA and counterimmunoelectrophoresis. Both tests could be useful in the diagnosis and the management of complicated S. aureus infections. The ELISA method is, however, more sensitive and usually reflects the antibody rise after an infection earlier than does counterimmunoelectrophoresis.
Collaborative clinical evaluation of the Autobac IDX system for identification of gram-negative bacilli
Authors: Kelly M T , Matsen J M , Morello J A , Smith P B , Tilton R C
Published: January 2020

The Autobac IDX system (General Diagnostics, Warner-Lambert Co., Morris Plains, N.J.) for rapid, semiautomated identification of gram-negative bacilli was compared with the identification methods in routine use in four laboratories. The study included 1,515 organisms representing 30 species of enteric and nonenteric bacteria. Discrepancies between the results of the IDX system and routine methods were resolved by classical biochemical testing at a reference center. Overall, 98% of the organisms were correctly identified by the routine methods, and 93% were correctly identified by the IDX systems. After adjustment for frequency of clinical occurrence of the organisms tested, the IDX system performed with 95% accuracy. Results with the IDX system were available in 3 to 6 h. Results with the comparative methods were available in 4 to 48 h. A wide variety of organisms, including oxidase positive, oxidase negative, fermentative, and nonfermentative, were identified by a single system by using Autobac. Three or more systems were required to identify the 30 species by the comparative methods. Overall, the results indicate the Autobac IDX system is useful for the rapid identification of enteric and nonfermentative gram-negative bacilli.
Detection of antibody to staphylococcal lipoteichoic acid with a microenzyme-linked immunosorbent assay
Authors: Carruthers M M , Jenkins K E , Kabat W J , Buranosky T
Published: January 2020

Sera from individuals with Staphylococcus aureus endocarditis and osteomyelitis and from some individuals with other forms of gram-positive endocarditis yielded higher readings in a microenzyme-linked immunosorbent assay against lipoteichoic acid from S. aureus than did sera from individuals with other types of serious staphylococcal infection or non-staphylococcal osteomyelitis, or from unselected inpatients.
Lipopolysaccharide banding patterns of Neisseria meningitidis and Neisseria gonorrhoeae
Authors: Parr T R , Bryan L E
Published: January 2020

The lipopolysaccharides of Neisseria meningitidis and Neisseria gonorrhoeae were examined by electrophoresis after whole-cell lysis and proteinase K digestion. The banding patterns observed from clinical isolates and laboratory strains demonstrated lipopolysaccharide which included a small number of smooth high-molecular-weight molecules as well as the previously reported lower-molecular-weight rough lipopolysaccharide.
Parasitic, bacterial, and viral enteric pathogens associated with diarrhea in the Central African Republic
Authors: Georges M C , Wachsmuth I K , Meunier D M , Nebout N , Didier F , Siopathis M R , Georges A J
Published: January 2020

A total of 1,197 diarrheic children less than 15 years old were investigated for parasitic, bacterial, and viral enteropathogens from March 1981 through February 1982 in the Central African Republic. One or more pathogens were identified from 49.4% of the patients. Rotavirus was the most frequently identified pathogen among children less than 18 months old. Enteropathogenic Escherichia coli was the second most frequently isolated pathogen (12.1%) in children less than 2 years of age. Campylobacter jejuni was also isolated frequently from diarrheic children less than 5 years of age (10.9%). Entamoeba histolytica was identified in very young children and was found to be the most frequent enteropathogen associated with diarrhea in children over the age of 2 years. Enterotoxigenic Escherichia coli was rarely isolated (ca. 2%). There was a peak in the incidence of rotavirus during the dry season and in the incidence of Campylobacter jejuni during the rainy season.
Semiautomated technique for identification of subgingival isolates
Authors: Dzink J L , Smith C , Socransky S S
Published: January 2020

A semiautomated approach for the characterization of subgingival bacterial isolates which economizes in media preparation, inoculation, reading, recording, and interpretation of results was tested. Test ingredients were added to a basal medium consisting of Mycoplasma broth supplemented with 5 micrograms of hemin, 0.5 mg of NaHCO3, and 0.5 mg of L-cysteine per ml. Sterile test media were aseptically dispensed into wells of sterile microtiter plates with a MIC 2000 dispenser. Inocula were grown in broth or scraped from agar plates, dispersed, and inoculated with a MIC 2000 inoculator. After 2 to 4 days of incubation, the optical density of growth was determined with an Artek 210 vertical beam reader at 580 nm and stored on a floppy disk. Reagents were added to each well, and the changes in optical density were determined. Thresholds for positive reactions were determined after extensive preliminary studies for each test. The tests were run in duplicate on each plate and interpreted with an Artek vertical beam reader. Tests that were run in this system included: fermentation of carbohydrates, decarboxylase reactions, reduction of nitrate and nitrite, ammonia production, hydrolysis of esculin, growth in the presence of inhibitory or stimulatory substances, and indole production. Approximately 80% of all isolates from subgingival samples could be characterized by this technique. Comparisons were made between the semiautomated and conventional identification techniques. Overall reproducibility of 2,980 strains by the semiautomated and conventional techniques were 95 and 90%, respectively. There was an 86% similarity of results by the semiautomated and conventional methods. The semiautomated technique was more rapid, less expensive, and as reproducible as the conventional method of identification.
Species distribution of coagulase-positive staphylococci in animals
Authors: Biberstein E L , Jang S S , Hirsh D C
Published: January 2020

A total of 268 isolates of coagulase-positive staphylococci from a variety of animal species, including dogs, horses, cats, monkeys, goats, and cows, were assigned to species on the basis of the API Staph- Ident system (Analytab Products, Inc., Plainview , N.Y.). Of 195 isolates from dogs, 179 (91.8%) were Staphylococcus intermedius, as were 9 of 25 (36%) isolates from horses, 7 of 15 (46.6%) isolates from cats, and 4 of 6 (66.6%) isolates from goats. Only 1 of 10 isolates from monkeys and none of 7 isolates from cows were S. intermedius. Of the remaining 68 cultures, 63 were identified as Staphylococcus aureus and 5 as Staphylococcus hyicus. The latter identifications were rendered doubtful on the basis of conventional tests. Identification appeared to be more certain in the S. aureus sample than in the S. intermedius sample. Distribution of biotypes within the two bacterial species as represented by different API profile numbers and reactivity on test substrates showed no significant variations among the host species, except for the S. aureus biotypes in dogs. Both Staphylococcus species were represented about equally among samples from different tissues and lesions, apart from skin-related infections in dogs, which were associated exclusively with S. intermedius (P less than 0.01). Differences between S. aureus and S. intermedius in antimicrobial susceptibility patterns, prevalence of clumping factor, and occurrence of beta-toxin were found to be not significant.
Characteristics of Haemophilus ducreyi in culture
Authors: Sturm A W , Zanen H C
Published: January 2020

Growth on different media and the influence of culture conditions were studied on 19 recently isolated strains of Haemophilus ducreyi, none of which had more than four passages on artificial media. The results were compared with 10 laboratory strains, which had an unknown number of passages in vitro. For all strains, growth was best on 30% rabbit blood agar and on Bieling agar. The laboratory strains showed a tendency to grow better on chocolate agar than did the fresh isolates. Of 19 fresh clinical isolates, 12 were CO2 dependent, and 2 needed extra moisture for growth. From the 10 laboratory strains, only one needed CO2 and none needed extra moisture. All 29 strains grew under anaerobic conditions. Of the 19 fresh clinical isolates, 12 grew at 22 degrees C, but only 2 of the 10 laboratory strains grew at this temperature. The laboratory strains grew better than the fresh isolates at 37 degrees C, and the optimal pH for all strains was pH 6.5 to 7.0. All strains showed starch aggregation.
Scanning and transmission electron microscopy of in situ bacterial colonization of intravenous and intraarterial catheters
Authors: Marrie T J , Costerton J W
Published: January 2020

Intravenous and intraarterial catheters were examined microbiologically and morphologically. Bacteria or yeasts were recovered from 38 of the 63 catheters examined, and Staphylococcus epidermidis was present on 29 of the 38 colonized catheters. Examination of unused Teflon catheters ( Jelco ; Surgikos , Inc., Peterborough , Ontario, Canada) showed surface irregularities, and the examination of colonized intravascular catheters recovered from patients showed very extensive amorphous accretions on both their lumenal and external plastic surfaces. Detailed scanning electron microscope examination of the accretions on vascular catheters from which S. epidermidis had been isolated showed (ca. 0.8 micron) coccoid bacteria within confluent biofilms , in which they were enveloped by amorphous material. Transmission electron microscope examination of these same accretions revealed coccoid cells (ca. 0.8 micron) with a gram-positive cell wall structure living in fibrous matrix-enclosed microcolonies in spaces between squamous epithelial cells. Staphylococcus aureus biofilms were seen to contain coccoid cells (ca. 1 micron) in a very extensive amorphous matrix, and a Candida parapsilosis biofilm contained very large numbers of large coccoid cells (ca. 4.3 microns) in a fibrous matrix resembling fibrin. Cells of a Corynebacterium species appeared to form much less extensive matrix-enclosed microcolonies on the colonized plastic surface. These data indicate bacteria and yeasts colonize intravascular catheters by an adherent biofilm mode of growth on these plastic surfaces.
Comparison of Cultureset and Bartels Immunodiagnostics with conventional tissue culture for isolation and identification of herpes simplex virus
Authors: Sewell D L , Horn S A , Dilbeck P W
Published: January 2020

Two 48-h Vero cell systems were compared with viral culture in human fibroblastic cells for isolation and identification of herpes simplex virus from clinical specimens. Both 48-h systems had 79% sensitivity and greater than 99% specificity as compared with the conventional tissue culture method.
Rapid screening of fecal samples for Vibrio cholerae by a coagglutination technique
Authors: Jesudason M V , Thangavelu C P , Lalitha M K
Published: January 2020

A coagglutination procedure for detecting Vibrio cholerae was applied directly to 125 watery fecal samples received in the laboratory for bacteriological culture: many of these were from suspected cases of cholera. Of 47 bacteriologically proved cases of cholera, 44 (93.6%) gave positive results by the coagglutination method. There was a good correlation between the coagglutination method, dark-field microscopy, and culture.
Evaluation of an enzyme-linked immunosorbent assay for the detection of herpes simplex virus antigen
Authors: Morgan M A , Smith T F
Published: January 2020

An enzyme-linked immunosorbent assay (ELISA) kit for herpes simplex virus developed by Ortho Diagnostic Systems, Inc., was evaluated. In phase I experiments, 263 clinical specimens from genital lesions were extracted into serum-free medium and then tested by ELISA for herpes simplex virus antigen. The results were compared with those obtained by conventional viral culture. Of 83 specimens, 65 were positive by ELISA (sensitivity, 78.3%). In phase II experiments, 249 clinical specimens were tested for herpes simplex virus antigen in direct specimen and in cell cultures (MRC-5 and rabbit kidney) incubated for 2, 4, and 7 days. Of 63 specimens, 40 were positive by ELISA in the direct specimen (sensitivity, 63.5%), and by 7 days incubation, 100% of the cultures positive by viral cell culture were also positive by ELISA. The ELISA was reproducible, and when both the direct detection and amplification culture were used, the sensitivity of ELISA paralleled the diagnosis of herpes simplex virus infections by viral cytopathic effect.
Differential primary plating medium for enhancement of pigment production by Pseudomonas aeruginosa
Authors: Daly J A , Boshard R , Matsen J M
Published: January 2020

A cost-effective and more rapid means of detection of Pseudomonas aeruginosa in cultures from clinical specimens would be very advantageous. We have developed a modified MacConkey agar (MMA), which enhances pigment production of P. aeruginosa and which, if pyocyanin pigment is present, provides a relatively rapid and very cost-effective identification. The MMA medium inhibits the gram-positive organisms, while lactose- and non-lactose-fermenting gram-negative rods are easily distinguishable from pigment-producing pseudomonads. Organisms that produce pyocyanin, pyoverdin, or pyorubin, or both pyocyanin and pyoverdin, are easily recognized on the medium. Pyocyanin production is clearly distinguishable from other Pseudomonas pigments on MMA. In a comparative study, MMA identified 97% of the P. aeruginosa strains 24 h earlier than routine laboratory biochemical methods. Highly mucoid strains which did not produce detectable pigments on standard biochemicals produced detectable pigments on the MMA within 48 h. This medium can provide a very practical, reliable, and cost-effective means for early characterization of P. aeruginosa.
Characterization and pathogenicity of Yersinia pseudotuberculosis isolated from swine and other animals
Authors: Tsubokura M , Otsuki K , Kawaoka Y , Maruyama T
Published: January 2020

Yersinia pseudotuberculosis serogroup III is most frequently detected in healthy pigs. Y. pseudotuberculosis strains were divided into two biogroups on the basis of their fermentation of melibiose. Melibiose-fermenting strains were distributed in all the hosts and serogroups examined. Melibiose-nonfermenting strains were limited to serogroup III isolated from healthy pigs. Autoagglutination and calcium dependency were not related to fermentation of melibiose. Melibiose-fermenting strains seem to be virulent for mice, but melibiose-nonfermenting strains showed no virulence for mice.
Clinical correlations of serial quantitative blood cultures determined by lysis-centrifugation in patients with persistent septicemia
Authors: Whimbey E , Wong B , Kiehn T E , Armstrong D
Published: January 2020

The potential clinical value of colony counts determined by the lysis-centrifugation blood culture method was studied by reviewing the records of eight patients with persistent septicemia in whom colony counts were available on at least 3 days. Colony counts of the five patients who survived decreased steadily as the patients improved. One of the three patients who died had counts repeatedly below 1.0 CFU/ml while she was clinically stable and higher counts when her condition deteriorated. Two patients died despite decreasing colony counts. One was improving and died unexpectedly of an unrelated cause; the other died of candidiasis, but declining serial arabinitol/creatinine ratios suggested a partial response to therapy. In addition, septicemia related to infected intravenous catheters was documented by demonstrating large differences in colony counts determined simultaneously from two different sites in two patients and by demonstrating a precipitous drop in CFU per milliliter after removal of the infected catheter in one patient. Routine availability of colony counts appears to be an important advantage of the lysis-centrifugation method.
Interpretive criteria and tentative quality control limits for apalcillin disk susceptibility tests
Authors: Barry A L , Thornsberry C , Jones R N , Gavan T L
Published: January 2020

In vitro studies with 661 bacterial isolates were performed to establish interpretive criteria. In addition, a nine-laboratory study was performed to establish quality control limits for tests with 100-micrograms apalcillin disks and to confirm testing criteria for tests with 100-micrograms piperacillin disks. The two drugs were very similar, and nearly identical criteria were recommended for interpretation and for control of the two types of disks. Neither disk is recommended for testing Staphylococcus spp. or Haemophilus spp.; with other microorganisms, zone size limits of less than or equal to 13 mm (resistant) and greater than or equal to 18 mm (susceptible) are proposed for tests with 100-micrograms apalcillin disks.
Suitability of the ASM-2 standard test of the National Committee for Clinical Laboratory Standards for evaluation of antimicrobial disk potency
Authors: Tardio J L , Westhoff D
Published: January 2020

Standard disks of 25 antimicrobial agents were prepared and tested at three levels of potency (67, 100, and 150% of labeled quantity). The method used was a modification of the approved standard M2-A2 of the National Committee for Clinical Laboratory Standards. Forty-seven susceptibility tests were performed at each potency level by using one to three test organisms. Labeled-potency (100%) disks were within accuracy limits for 85% of the tests and were within daily control limits for 94% of the tests. All susceptibility test data for labeled disks, however, were considered acceptable. The majority (63%) of mean zone diameter data for labeled-content disks were in the upper-one-third percentile of accuracy control limits. A significant proportion (91%) of low-potency disks and considerably fewer (34%) of the high-potency disks were found acceptable when daily control limits were applied. Of most concern are those antimicrobial agents whose low-potency disks approach the lower region of control limits. Zone diameter data from standard disks in the range of potency levels tested suggest that control ranges are excessive for some antimicrobial agent-test organism combinations.
Use of absorbed antisera for demonstration of antigenic variation among strains of Legionella pneumophila serogroup 1
Authors: Thomason B M , Bibb W F
Published: January 2020

Antigenic typing of strains of Legionella pneumophila serogroup 1 (Lp1) has been shown to be useful in epidemiological studies of outbreaks of legionellosis. Selective absorption of rabbit antibodies produced against five strains of Lp1 resulted in the recognition of 17 somatic types among the 176 strains tested. A comparison was made of our results and those obtained by McKinney et al. (Zentralbl. Bakteriol. Parasitenkd. Infektionskr. Hyg. Abt. 1 Orig. Reihe A 255:91-95, 1983) and Joly et al. (J. Clin. Microbiol. 18:1040-1046, 1983), who used monoclonal antibodies to subgroup Lp1 strains. The results indicate that antigens are present in Lp1 strains that were undetected by either system. The data presented in this study may be helpful in selecting for the production of additional monoclonal or absorbed antibodies for diagnostic purposes or epidemiological studies.
Reevaluation of the ability of the standardized disk diffusion test to detect methicillin-resistant strains of Staphylococcus aureus
Authors: Boyce J M
Published: January 2020

To reevaluate the ability of the disk diffusion method to detect methicillin-resistant Staphylococcus aureus, 73 such isolates from 13 cities were tested for antimicrobial susceptibility with the standardized disk diffusion test. Duplicate plates were incubated at 30 and 35 degrees C and read after 18, 24, and 48 h. After incubation at 35 degrees C for 24 h, 97% of isolates appeared resistant to methicillin, and 99% appeared resistant to oxacillin. A significantly smaller proportion of isolates appeared resistant to cephalothin (P less than 0.001) and cefamandole (P less than 0.001). Isolates from some cities had no zones of inhibition around methicillin and oxacillin disks, whereas those from other cities had measurable zones of inhibition, with light growth inside the zones. Patterns of growth around cephalothin and cefamandole disks also varied among isolates from different cities. Incubation at 30 degrees C for 24 h did not result in better detection of methicillin or oxacillin resistance. All study isolates appeared resistant to methicillin and oxacillin after 48 h of incubation at 35 degrees C. The results suggest that methicillin-resistant S. aureus strains from many areas will be detected if standardized disk diffusion tests are incubated at 35 degrees C for 24 h.
Unusual susceptibility of methicillin-resistant Staphylococcus aureus to erythromycin, clindamycin, gentamicin, and tetracycline at 30 degrees C but not at 35 degrees C
Authors: Welch W D , Southern P M
Published: January 2020

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in hospital environments, and optimal detection of MRSA requires nonroutine methods in clinical microbiology laboratories. One such method is an incubation temperature of 30 degrees C in contrast to the more commonly used temperature of 35 degrees C. To determine the percentage of MRSA isolates that would be missed if only one temperature were used, we evaluated methicillin resistance and susceptibility of 2,397 S. aureus isolates by agar dilution at 30 and 35 degrees C. Of the clinical isolates, 93% showed matching MICs of methicillin at both temperatures. Another 6.8% (162) showed different MICs at 30 and 35 degrees C, with 60 of the 162 isolates (2.5% of all isolates studied) being resistant to methicillin at 30 degrees C but susceptible at 35 degrees C (temperature-discrepant MRSA). MICs of other antimicrobial agents, measured at 35 degrees C, revealed an unusual pattern of susceptibility of these temperature-discrepant MRSA isolates. In contrast to previously reported resistance of MRSA at 35 degrees C to erythromycin, clindamycin, gentamicin, and tetracycline, the temperature-discrepant MRSA isolates were susceptible to these agents. This resistance pattern may be of value in identifying questionable MRSA isolates when only one incubation temperature is used.
Development of an enzyme-linked immunosorbent assay for determination of lysozyme in human parotid and submandibular-sublingual salivas
Authors: MacKay B J , Goodman H , Cox D , Grossbard B L , Iacono V J , Pollock J J
Published: January 2020

The specificity of lysozyme determinations in human parotid and submandibular-sublingual salivas of two subjects was assessed by comparison of lysozyme concentrations in native acidified salivas with purified enzyme obtained by immunoadsorbent fractionation of the salivas. Lysozyme concentrations were measured by the turbidimetric catalytic method and by a newly developed enzyme-linked immunosorbent assay (ELISA). The validity of the assays was established by comparing assay results with enzyme concentration values determined from optical density-extinction coefficient calculations of the purified lysozyme peak. Values for purified enzyme were found to be similar, irrespective of the assay used to determine lysozyme concentrations, and were in agreement with extinction coefficient calculations. Based on the ELISA technique, recoveries of lysozyme from both parotid and submandibular-sublingual salivas were greater than 75 and 90%, respectively. Similar recoveries were noted for parotid saliva when determinations were based on the turbidimetric assay. However, the ELISA and turbidimetric assays differed with respect to lysozyme levels in submandibular-sublingual saliva because of the apparent presence of an enhancement factor which gave rise to higher lysozyme values in the catalytic assay and therefore resulted in low recoveries of purified enzyme. This catalytic enhancement factor was present in the nonadsorbed fraction of both subjects, as higher lysozyme activities were noted when nonadsorbed fractions were added to affinity-purified lysozymes. Lysozyme levels were also determined in the parotid and submandibular-sublingual salivas of caries-resistant and -susceptible adults. In general, levels of lysozyme in parotid saliva were lower in comparison to submandibular -sublingual saliva; however, significant differences in enzyme concentration were not evident between the caries-resistant and caries-susceptible subjects.
Evaluation of the hemagglutination treponemal test for syphilis
Authors: Moyer N P , Hudson J D , Hausler W J
Published: January 2020

The sensitivity and specificity of the hemagglutination treponemal test for syphilis (HATTS) was compared with the fluorescent treponemal antibody-absorption test (FTA-ABS) with 491 sera. Medical histories were obtained for 153 patients with seroreactivity in either treponemal test. Overall correlation with patient history was 96.7% for the FTA-ABS and 93.9% for the HATTS. False-negative HATTS occurred in primary, late-latent (greater than 2 years), and treated syphilis. The reproducibility of the HATTS and FTA-ABS is equivalent. HATTS is an acceptable treponemal confirmatory test for syphilis, but the FTA-ABS should be used to resolve diagnostic discrepancies.
Collaborative evaluation of the Abbott yeast identification system
Authors: Cooper B H , Prowant S , Alexander B , Brunson D H
Published: January 2020

The Abbott yeast identification system (Abbott Laboratories, Diagnostics Division, Irving, Tex.) is a 24-h, instrumental method for identifying medically important yeasts, based on matrix analysis of 19 biochemical reactions and the germ tube test. The system was evaluated in two clinical laboratories by using 179 coded isolates, which included a high percentage of the less frequently encountered species. Based upon results with these coded isolates and from previously obtained laboratory data, the system software was adjusted and accuracy of the yeast identification system was further evaluated with 378 isolates from clinical sources. Of the 378 clinical yeast isolates tested, 364 (96%) were correctly identified with the Abbott system. Isolates were deliberately selected so that germ tube-positive isolates made up less than 10% of the clinical isolates tested.
Factors influencing quantitative isolation of varicella-zoster virus
Authors: Levin M J , Leventhal S , Masters H A
Published: January 2020

Optimal conditions are described for the recovery of cell culture-derived varicella-zoster virus (VZV). Of the cells tested, human embryonic lung fibroblasts were the most sensitive. Storage and handling procedures were examined to determine the stability of VZV in viral transport medium. When the initial VZV titer was high (2 X 10(4) PFU/ml) 40% of the VZV survived room temperature for 24 h and 75% of the VZV remained viable for this long at 4 degrees C. Recovery was 5- to 10-fold less at lower initial VZV titers (less than 2 X 10(3) PFU/ml). Other factors which influenced VZV recovery included freezing at -20 degrees C, the use of cotton or calcium alginate swabs, and filtration to remove bacterial contaminants. The tissue culture methods described were used in a reconstruction experiment to demonstrate that VZV could be recovered from a laboratory coat or human skin (0.1 to 0.3% of input VZV) or from a stethoscope (19% of input VZV) as late as 30 min after inoculation. During a clinical trial using optimal VZV recovery procedures, 76% of the patients with herpes zoster yielded VZV when first cultured, and 60% remained culture positive for an additional 48 h.
Detection of rotavirus in human stools by using monoclonal antibody
Authors: Cukor G , Perron D M , Hudson R , Blacklow N R
Published: January 2020

A monoclonal antibody, 3F7, that reacts with the common rotavirus antigen on the sixth viral gene product was prepared. It was used in a direct monoclonal antibody radioimmunoassay (RIA) as a diagnostic reagent for detection, in 3.5 h, of rotavirus in human pediatric stool specimens. In the 177 samples tested, a concordance of 96% was seen between the monoclonal RIA and the well-established and commonly used commercially available Rotazyme test. Six discrepant specimens that were positive by monoclonal RIA but negative by Rotazyme were shown to be positive by either electron microscopy or confirmatory blocking immunoassay. A seventh discrepant specimen was positive by Rotazyme and negative by monoclonal RIA as well as by both direct and immune electron microscopy. The monoclonal RIA test appears to be highly sensitive and specific, and merits additional evaluation as a rapid, convenient diagnostic assay that can reduce currently encountered problems associated with diagnosing rotavirus infection by immunoassay.
Differentiation of Brucella ovis from Brucella abortus by gas-liquid chromatographic analysis of cellular fatty acids
Authors: Coloe P J , Sinclair A J , Slattery J F , Burke D
Published: January 2020

The cellular fatty acid composition of Brucella ovis and Brucella abortus strains was determined by gas-liquid chromatography. Both species were characterized by the presence of fatty acids 16:0, 17:0, 17:0 cyclopropane, 18:0, 18:1, and 19:0 cyclopropane; B. ovis also contained some 15:0. There were differences in the relative proportions of the fatty acids present, and it was possible to differentiate B. ovis from B. abortus on the basis of the absence of 15:0, lower concentrations of 17:0 and 18:1, and higher concentrations of 19:0 cyclopropane in B. abortus. The data indicate that analysis of cellular fatty acid composition by gas-liquid chromatography can be used for the identification of B. ovis and its differentiation from B. abortus.
Prediction of sulfamethoxazole-trimethoprim synergistic action against members of the family Enterobacteriaceae with a two-plate agar dilution breakpoint MIC system
Authors: Ward P B , Carson M , Dodd J S , Pavillard E R
Published: January 2020

Synergy between sulfamethoxazole (SMZ) and trimethoprim (TMP) was predicted by a two-plate agar dilution breakpoint MIC system. Comparison of the results of this new system with those of the disk diffusion system (P.M. Waterworth, Postgrad. Med. J. Suppl. 45:21-27, 1969) after tests with 1,518 Enterobacteriaceae isolates showed an overall correlation of 99.8%, a sensitivity of 99.7%, and a specificity of 100%. The method involves spot inoculation of 10(3) organisms onto each of two plates, one containing 160 micrograms of SMZ per ml and the other 8 micrograms of TMP per ml (in Oxoid IsoSensitest medium with 3% agar supplemented with 7% saponin-lysed horse blood), and then incubation overnight at 37 degrees C in air. All but three organisms for which SMZ-TMP was found to be synergistic by disk testing were inhibited on both plates. Three isolates of Proteus mirabilis, which failed to correlate with disk testing by this new system, all showed SMZ MICs of 1,000 micrograms/ml. The SMZ-TMP combination was falsely predicted to be nonsynergistic against these three organisms. There were no false synergy predictions by the breakpoint MIC system. Laboratories should report susceptibility to the SMZ-TMP combination only when there is synergy between the constituents. This simple, reliable agar dilution technique enables laboratories to accurately report synergy between SMZ and TMP.
Problems in determining immune status in borderline specimens in an enzyme immunoassay for rubella immunoglobulin G antibody
Authors: Steece R S , Talley M S , Skeels M R , Lanier G A
Published: January 2020

A total of 374 sera, found by enzyme-linked immunosorbent assay (Rubazyme; Abbott Laboratories, North Chicago, Ill.) to have borderline rubella antibody levels, were tested by hemagglutination inhibition. All sera had Rubazyme indexes in the range of 0.500 to 1.499. Rubazyme sensitivity was 59.0%, and specificity was 80.8%. The predictive value of Rubazyme-positive result was 91.4%, and that for a negative result was 36.4%. Immune and nonimmune results were significantly different between the two methods (P less than 0.001). The same sera were retested with the Rubazyme test, with an inter-run agreement of 75.3%. A significant difference in Rubazyme indexes between runs (P less than 0.001) was observed. An alternative method of testing specimens in the range close to the Rubazyme index cutoff value of 1.000 may be indicated.
Pasteurella pneumotropica isolated from bone and joint infections
Authors: Gadberry J L , Zipper R , Taylor J A , Wink C
Published: January 2020

Pasteurella pneumotropica is a normal inhabitant of the oropharynx of mice, rats, cats, and dogs. We describe here the first reported case of joint and bone involvement in a human. The need for culturing and adequate prophylactic treatment is discussed.
Comparison of monoclonal and polyclonal antibody for confirmation of cytomegalovirus isolates by fluorescent staining
Authors: Fiacco V , Bryson Y J , Bruckner D A
Published: January 2020

A fluorescein isothiocyanate-labeled monoclonal cytomegalovirus antibody reagent incorporating Evans blue (Syva/Genetic Systems, Palo Alto, Calif.) was compared to a fluorescein isothiocyanate-labeled polyclonal antibody (Dynatech Diagnostics, Inc., South Windham, Maine) for identification of cytomegalovirus in tissue culture. A total of 191 cultures, 86 positive and 105 negative for cytomegalovirus by cytopathic effect in WI38 cells, were stained in parallel and examined by fluorescent microscopy. No false-negative results were noted with either reagent; however, the polyclonal antibody-stained slides required the use of a separate counterstain to decrease nonspecific fluorescence. The polyclonal reagent gave a false-positive reaction with one varicella-zoster virus isolate and four simian cytomegalovirus isolates. No false-positive results were noted with the monoclonal reagent.