bluuebunny/crossref_metadata_2025 huggingface dataset:
Modified enzyme-linked immunosorbent assay for detecting enteroinvasive Escherichia coli and virulent Shigella strains
Authors: Pál T , Pácsa A S , Emödy L , Vörös S , Sélley E
Published: January 2020

Immune sera were produced in rabbits with living cells of an enteroinvasive O143 strain of Escherichia coli. To remove O and K antibodies, sera were absorbed with an avirulent derivative of the same strain. In the enzyme-linked immunosorbent assay, absorbed sera reacted specifically with only virulent Shigella strains and enteroinvasive E. coli strains of different geographical origin, regardless of species or serogroups. The investigation of 83 strains indicated complete agreement between enzyme-linked immunosorbent assay results and those of the keratoconjunctivitis test. It is assumed that the absorbed immune sera reacted with a possible virulence marker antigen. This inexpensive and simple method provides an alternative to other virulence tests. It has a definite advantage for screening large number of isolates within 24 h.
Radioenzymatic assays for aminoglycosides with kanamycin 6'-acetyltransferase
Authors: Weber A , Smith A L , Opheim K E
Published: January 2020

To facilitate the rapid and accurate quantitation of parenterally administered aminoglycosides, we defined the optimum conditions (pH, duration of incubation, and cofactor concentrations) to permit radioenzymatic assays with kanamycin acetyltransferase. The accuracy in quantitating tobramycin, netilmicin, kanamycin, and amikacin at concentrations in the therapeutic range was greater than 90%, with a mean recovery of 102.8%. The mean of the interassay coefficient of variation was 7.8%. Typical standard curves at six different concentrations resulted in a correlation coefficient (r value) of greater than 0.99 for each aminoglycoside. The radioenzymatic assay correlates well with the bioassay (tobramycin and netilmicin) and radioimmunoassay (amikacin and kanamycin); the correlation coefficient is greater than 0.90 for all. We conclude that the radioenzymatic assay utilizing kanamycin 6'-acetyltransferase is feasible for all commercially available parenterally administered aminoglycosides.
Comparison of the Scott Selecticult-HSV kit with conventional culture and direct immunoperoxidase staining for detection of herpes simplex virus in cultures of clinical specimens
Authors: Johnson F B , Leavitt R W , Richards D F
Published: January 2020

In a comparative study, clinical specimens were cultured for herpes simplex virus (HSV). The presence of virus was noted by the appearance of characteristic cytopathic effect, as determined by standard direct immunofluorescence techniques, by using a direct immunoperoxidase stain for viral antigen, or by using the Selecticult-HSV (SC-HSV) stain for viral antigen. There was 100% correlation between the SC-HSV stain and immunofluorescence staining in recognizing HSV-infected cells (81 of 81 positive specimens). In comparison with observation of cytopathic effect, the SC-HSV system and conventional culture detected 93 and 78% of positive cultures at 48 h postinoculation and 76 and 32%, respectively, at 24 h. By 5 days postinoculation, SC-HSV detected 100% of the positive specimens. As compared with the direct immunoperoxidase stain, SC-HSV stain was slightly more sensitive and gave less background stain. HSV serotypes 1 and 2 were both detected by the SC-HSV stain. The Scott SC-HSV kit appears to be an effective system for the diagnosis of HSV infections.
Inability to adequately control antimicrobial agents on AutoMicrobic System Gram-Positive and Gram-Negative Susceptibility Cards
Authors: Kellogg J A
Published: January 2020

The Vitek Gram-Positive Susceptibility Card (GPS) and Gram-Negative General Susceptibility Plus Card (GSC Plus) were tested on the AutoMicrobic System (AMS) 50 times each with the recommended control organisms. Only 1 drug (chloramphenicol) of 11 on the GPS and 1 (gentamicin) of 10 on the GSC Plus could be adequately controlled, leaving unsubstantiated the results obtained with patient isolates on the remaining 19 antimicrobial agents.
Characterization of Micrococcaceae strains isolated from the human urogenital tract by the conventional scheme and a micromethod
Authors: Baldellon C , Mégraud F
Published: January 2020

Two hundred and twelve Micrococcaceae isolates were obtained from 82 men with nongonococcal urethritis, 24 women with vaginitis, and 54 girls with vulvovaginitis. Identification and biotyping of these strains were carried out by using the simplified scheme of Kloos and Schleifer (W. E. Kloos and K. H. Schleifer, J. Clin. Microbiol. 1:82-88, 1975) and the commercially available API Staph test (DMS Staph Trac). Staphylococcus epidermidis occurred in about half of these isolates. There was no statistical difference between the urethral and vaginal specimens, except for S. haemolyticus found primarily in males and for S. simulans and S. aureus found primarily in girls between the ages of 1 and 12 years. S. saprophyticus, a major cause of urinary tract infections in young women, was never isolated from the vagina, suggesting the probability of another reservoir.
Surveillance of nosocomial infections by computer analysis of positive culture rates
Authors: Schifman R B , Palmer R A
Published: January 2020

We describe a surveillance method that identifies excessive rates of positive cultures based on patient location, culture site, and organism identification. During a 6-month period, this surveillance method, coupled with epidemiological investigations, identified 19 small clusters of cross-infections and three small outbreaks of intravenous catheter-related bacteremias. These infections were associated with apparent breakdowns in proper technique. Concurrent, standard surveillance activities identified only three of these problems. These results demonstrate that computer analysis of positive culture rates is a sensitive and time-efficient method for detecting potentially preventable nosocomial infections.
Bioluminescence screening for bacteriuria
Authors: Kolbeck J C , Padgett R A , Estevez E G , Harrell L J
Published: January 2020

A rapid screening test (45 min) for bacteriuria was evaluated in 1,000 clinical urine specimens. The test procedure is based upon firefly luciferase analysis of bacterial ATP and uses the Lumac kit and Lumac M2010 Biocounter (3M Co., St. Paul, Minn.). The procedure allows for removal and destruction of nonbacterial ATP and subsequent analysis of bacterial ATP by firefly luciferase with a single photon counter. Results, expressed in relative light units, were compared with actual CFU by the calibrated loop technique. Sensitivities and specificities were calculated separately for clean-catch midstream specimens and for urines obtained by catheterization. The sensitivity for 719 clean-catch specimens with a Lumac cutoff of greater than or equal to 500 relative light units, representing greater than or equal to 10(5) CFU/ml, was 93%. The sensitivity for 281 catheterized specimens with a Lumac cutoff of greater than or equal to 200 relative light units, representing greater than or equal to 10(4) CFU/ml, was 95%. There were 19 false-negative results in the 1,000 specimens tested; more than 50% of these were contaminated cultures and were not considered significant in determining bacteriuria. In conclusion, the Lumac bioluminescence assay is a reliable, rapid bacteriuria screening technique with the potential of reducing the laboratory cost and for reducing the turnaround time in processing negative urine cultures.
Controlled evaluation of supplemented peptone and Bactec blood culture broths for the detection of bacteremia and fungemia
Authors: Reimer L G , McDaniel J D , Mirrett S , Reller L B , Wang W L
Published: January 2020

Comparison of conventional blood culture media with newer formulations of Bactec media for radiometric detection are lacking. Therefore, we compared the yield and speed of detection of clinically important microorganisms with supplemented peptone broth (SPB) and Bactec aerobic (6B) and anaerobic (7C or 7D) broths in 7,627 blood samples from adult patients. Acridine orange stains from SPB, radiometric readings from Bactec, and routine subcultures from all bottles were done at the same time intervals. Bactec grew more facultative gram-positive bacteria (P less than 0.02), Bacteroides spp. (P less than 0.001), gram-negative anaerobes (P less than 0.001). The two-bottle Bactec system required less time to detect Staphylococcus aureus (P less than 0.001), facultative gram-positive bacteria (P less than 0.001), Escherichia coli (P less than 0.02), facultative gram-negative bacteria (P less than .001), and fungi (P less than 0.001). Overall, Bactec yielded 11% more microorganisms and detected bacteremia sooner in 18% of samples than did SPB. This advantage was not because of radiometric monitoring, since most positive Bactec bottles were detected macroscopically. SPB offered no advantage for any group of microorganisms. We conclude that Bactec 6B and 7C or 7D broths used as a unit are superior to a single bottle of SPB with an equal volume of blood for the detection of bacteremia and fungemia, and that Bactec's superiority is not due to the method of detection.
Comparison of the API rapid E four-hour system with the API 20E overnight system for the identification of routine clinical isolates of the family Enterobacteriaceae
Authors: Overman T L , Plumley D , Overman S B , Goodman N L
Published: January 2020

Four hundred forty-one clinical isolates of the family Enterobacteriaceae were identified in parallel by using the API Rapid E 4-h and the API 20E overnight procedures (Analytab Products, Plainview, N.Y.). The results obtained by using the API Rapid E were compared with those obtained by using the API 20E. Discrepancies were resolved by using standard biochemicals. The API 20E identified 98.9% (436 of 441) of the isolates without the use of additional biochemicals and was found to be correct in each case of a discrepancy among the 436 isolates. The API Rapid E gave the same identification as the API 20E for 94.0% (410 of 436) of the isolates, misidentified 3.0% (13 of 436), and gave a correct but low-selectivity answer for the remaining 3.0% (13 of 436). The API Rapid E is a suitable alternative for the rapid identification of the Enterobacteriaceae.
Controlled evaluation of Trypticase soy broth in agar slide and conventional blood culture systems
Authors: Weinstein M P , Reller L B , Mirrett S , Wang W L , Alcid D V
Published: January 2020

A commercially available biphasic blood culture system that utilizes an attachable agar slide paddle and Trypticase soy broth (BBL Microbiology Systems, Cockeysville, Md.) was compared with a conventional Trypticase soy broth blood culture bottle in 6,867 paired blood cultures from adult patients. Both systems were inoculated with equal volumes of blood (5 ml) and incubated aerobically (vented) for 2 weeks. More clinically important bacteria and fungi, including Staphylococcus epidermidis, streptococci, Escherichia coli, Klebsiella spp., other Enterobacteriaceae, and Pseudomonas aeruginosa, were recovered from the biphasic system (P less than 0.001). In contrast, more anaerobic bacteria of importance were recovered in the conventional bottle (P less than 0.01). Staphylococci (P less than 0.001), gram-negative facultative and aerobic bacteria (P less than 0.001), and fungi (P less than 0.001) were detected 1 or more days earlier in the biphasic system, whereas pneumococci (P less than 0.05) were detected earlier in the conventional bottle. Of 603 clinically important microorganisms that grew in the biphasic system, 601 (99.7%) were detected by day 7 of incubation, but only 403 of 490 microorganisms (82.2%) were detected by day 7 in the conventional bottle. Overall, the biphasic system was superior to the conventional bottle. For optimal detection of anaerobic bacteremia, however, the biphasic system should be used in conjunction with a complementary anaerobic conventional bottle.
Detection of Haemophilus influenzae type b antigenuria by Bactigen and Phadebact kits
Authors: Riera L
Published: January 2020

Two commercially available reagents, latex particles (Bactigen) and Staphylococcus aureus suspensions (Phadebact), were compared for the detection of the capsular polyribitol phosphate antigen of Haemophilus influenzae type b in 18 pediatric patients with proven infections due to H. influenzae type b. Whereas both tests nearly equally detected the antigen in the first urine specimens from the patients, the latex test remained positive significantly longer than did the Phadebact test for serial urine specimens. We conclude that the Bactigen test is slightly more sensitive than the Phadebact test for detecting urinary H. influenzae type b antigen.
Adaptation of a coculture technique to the Minitek anaerobe system
Authors: Hussain Z , Lannigan R , Bürger H , Groves D
Published: January 2020

A method to produce anaerobic conditions by coculture with a nonfermentative organism was utilized in conjunction with the Minitek anaerobe system (BBL Microbiology Systems, Cockeysville, Md.) for identification of anaerobic bacteria from clinical specimens. With the coculture method, the Minitek anaerobe identification tests could be incubated under aerobic conditions. In 1,900 individual biochemical reactions, 1,826 (96%) were identical whether anaerobic conditions were achieved by conventional or coculture techniques. In comparison with the reference identification (Virginia Polytechnic Institute and State University, Blacksburg), both systems of incubation identified 91 of 99 strains (92%) correctly. The method of incubation had an effect on identification to the genus level in 1 of 99 (1%) strains and to the species level in 3 of 99 (3%) strains.
Isolation of Serratia plymuthica from a human burn site
Authors: Clark R B , Janda J M
Published: January 2020

The saprophytic bacterium Serratia plymuthica was recovered from a facial wound (burn) site of a pediatric patient. The clinical significance of the organism was undetermined due to its apparent eradication from this location by therapy with topical 1% silver sulfadiazine. Seeding of the burn with S. plymuthica may have occurred from contaminated moisture sometimes found on and around steam radiators.
Difference in virulence of environmental isolates of Legionella pneumophila
Authors: Bollin G E , Plouffe J F , Para M F , Prior R B
Published: January 2020

Endemic nosocomial Legionnaires disease has occurred at our medical center for several years. Two subtypes of Legionella pneumophila serogroup 1 (UH-1 and RH-1) have been isolated in approximately equal numbers from hospital potable water. However, almost all clinical isolates have been UH-1. To assess potential differences in virulence, 50% lethal doses (LD50) and 50% infective doses (ID50) of UH-1 and RH-1 were determined by intraperitoneal infection in guinea pigs. The UH-1 LD50 was 7.41 X 10(6) CFU, which was significantly lower than the RH-1 LD50 of 9.12 X 10(7) CFU (P = 0.0001). The mean time to death in UH-1-infected guinea pigs was also significantly shorter than in RH-1-infected animals (P = 0.0008). The UH-1 ID50 was 5.8 X 10(3) CFU, and although it was lower than the RH-1 ID50 of 1.4 X 10(4) CFU, this difference was not statistically significant (P = 0.21). This study demonstrates a difference in virulence between UH-1 and RH-1 in guinea pigs. Differences in strain virulence, as demonstrated between these two subtypes, may help to explain the widespread isolation of L. pneumophila from the environment contrasted with the limited occurrence of human Legionnaires disease.
Effect of sodium polyanetholesulfonate and gelatin on the recovery of Gardnerella vaginalis from blood culture media
Authors: Reimer L G , Reller L B
Published: January 2020

Sodium polyanetholesulfonate (SPS) is used as a routine supplement to blood culture media to enhance recovery of microorganisms, but it inhibits the growth of Peptostreptococcus anaerobius, Neisseria meningitidis, Neisseria gonorrhoeae, and Streptobacillus moniliformis. Comparative clinical blood culture studies at the University of Colorado Hospital suggested that SPS also inhibits the growth of Gardnerella vaginalis. We inoculated 16 blood culture isolates of G. vaginalis into 11 blood culture media containing SPS or sodium amylosulfate, with and without gelatin. In the absence of gelatin, only brain heart infusion and thiol broths with SPS supported the growth of more than five strains of G. vaginalis, whereas all media except Bactec 6B and 7C and brucella broths recovered most isolates with SPS and gelatin or with sodium amylosulfate alone. We conclude that SPS inhibits the growth of G. vaginalis in blood culture media but that this inhibition is medium dependent and can be overcome by supplementation of most media with gelatin.
Application of an objective biological assay of human interferons to clinical specimens and a survey of a normal population
Authors: Forti R L , Moldovan R A , Mitchell W M , Callicoat P , Schuffman S S , Davies H A , Smith D M
Published: January 2020

A rapid, quantitative, and nonsubjective method of interferon assay is described, which can be readily applied to clinical specimens. Automated data acquisition and data reduction allowed a significant increase in volume per unit of time over existing methodologies. Plasma always yielded higher (usually 2:1) interferon values than did serum obtained simultaneously. Ranges of interferon levels in plasma in normal control populations are reported as well as ranges for clinical virology laboratory technicians and patients with terminal malignancies or collagen vascular diseases.
Comparison of a new, rapid enzyme-linked immunosorbent assay with latex particle agglutination for the detection of Haemophilus influenzae type b infections
Authors: Macone A B , Arakere G , Letourneau J M , Goldmann D A
Published: January 2020

A new, rapid enzyme-linked immunosorbent assay (ELISA) for the detection of polyribosylribitol phosphate of Haemophilus influenzae type b was compared with a commercially available latex particle agglutination (LPA) system (Bactigen; Wampole Laboratories, Cranbury, N.J.). By adding specimens and the anti-polyribosylribitol phosphate immunoglobulin-enzyme conjugate to the solid phase in a single step, it was possible to complete the ELISA procedure in 30 min. The ELISA was capable of detecting 0.3 ng of polyribosylribitol phosphate per ml in cerebrospinal fluid, 0.6 ng/ml in urine, and 1.2 ng/ml in serum; the in vitro sensitivity of LPA in these body fluids was 0.6, 0.3, and 0.3 ng/ml, respectively. Both procedures detected polyribosylribitol phosphate in specimens from 25 patients with bacteriologically confirmed H. influenzae type b infections. The specificity of ELISA appeared to be superior to that of LPA. ELISA was positive in only one of seven patients who had a positive LPA test and a clinical illness that was not compatible with haemophilus infection. Moreover, five patients with bacteriologically confirmed infections due to other pathogens (Streptococcus pneumoniae type 14 [two patients], Neisseria meningitidis group C, Escherichia coli K100, and Staphylococcus aureus) had false-positive LPA tests; only two (E. coli and S. aureus) were positive by ELISA. A total of 108 samples from 61 patients who had no evidence of haemophilus infections were negative by both procedures. The ELISA is a rapid, sensitive, and specific alternative to LPA for the detection of haemophilus polyribosylribitol phosphate.
Determination of monounsaturated double-bond position and geometry in the cellular fatty acids of the pathogenic bacterium Francisella tularensis
Authors: Nichols P D , Mayberry W R , Antworth C P , White D C
Published: January 2020

The nonhydroxy fatty acid composition of Francisella tularensis is reported in detail. The double-bond configuration of the monounsaturated acids has been determined by capillary gas chromatography-mass spectrometry of the derivatized fatty acids. The monounsaturated fatty acids detected, in decreasing order of abundance, were 24:1 omega 15c, 18:1 omega 9c, 22:1 omega 13c, 20:1 omega 11c, 16:1 omega 7c, 26:1 omega 17c, and 14:1 omega 7c. The fatty acid profile found in F. tularensis, in particular the double-bond positions, represents a valuable taxonomic characteristic of this pathogenic bacterium.
Simple microbiological method for the identification of antimicrobial agents prescribed in general practice
Authors: Millar M R , Langdale P
Published: January 2020

A simple microbiological method to identify antimicrobial agents in urine is described. Of 1,514 consecutive urine specimens received from general practitioners, 302 (19.94%) contained antimicrobial activity. The antibacterial agent was identified confidently in 284 of these. Surprisingly, 83 (5.48%) urine specimens contained an antimicrobial substance not usually used in the treatment of urinary tract infection.
Cross-reactions between alpha-streptococci and Omniserum, a polyvalent pneumococcal serum, demonstrated by direct immunofluorescence, immunoelectroosmophoresis, and latex agglutination
Authors: Holmberg H , Danielsson D , Hardie J , Krook A , Whiley R
Published: January 2020

In recent years several groups have used serological methods to demonstrate pneumococcal capsular antigens in sputum. In the present study 123 strains of alpha-hemolytic streptococci (including 97 strains from sputum or pharyngeal specimens) were tested for cross-reactions with a polyvalent antipneumococcal serum (Omniserum). Representatives of the following species were included: Streptococcus bovis, S. equinus, S. intermedius, S. lactis, S. milleri, S. mitis, S. mutans, S. sobrinus, S. salivarius, S. sanguis, S. suis, and Aerococcus viridans. Serological reactions were detected by direct immunofluorescence, immunoelectroosmophoresis, and latex agglutination. Fifteen (12%) of the strains gave positive reactions by all three methods. Positive reactions were also observed with another 32 strains (26%) with two of the methods, whereas 37 strains (30%) gave positive reactions by just one technique. Altogether 84 (68%) strains gave positive reactions with one or more of the methods. Latex agglutination gave positive reactions with 26 (21%) strains compared with 57 (46%) in immunofluorescence and 63 (51%) in immunoelectroosmophoresis. Absorption of the antiserum with one alpha-hemolytic strain reduced but did not entirely eliminate the cross-reactions with five tested strains. These findings indicate a potential risk of cross-reactions with polyvalent antipneumococcal serum in tests carried out on sputa or other specimens which may be contaminated with alpha-hemolytic streptococci.
Diagnosis of systemic candidiasis by latex agglutination for serum antigen
Authors: Bailey J W , Sada E , Brass C , Bennett J E
Published: January 2020

Three latex agglutination test procedures for detecting Candida antigen in human serum were compared in a retrospective study of 69 patients and 20 normal volunteers. Untreated human serum was reacted with two different latex reagents; one reagent also was reacted with serum treated with protease and heat. The test procedure with treated serum was best, detecting serum antigen in 17 of 21 patients (81%) with disseminated candidiasis. Judging by autopsy-proven cases, there was an increase in positive test results in the last 2 weeks of life. When untreated sera were tested with this reagent, only 3 (14%) of the 21 patients with disseminated candidiasis had detectable antigen in serum. A subset of these same sera was tested by a commercial latex reagent (Candida Detection System lot C001; Ramco Laboratories, Inc., Houston, Tex.) and untreated serum. Of 18 patients with disseminated candidiasis, 5 (28%) had at least one positive serum. Sera from patients with less severe clinical forms of candidiasis were usually negative regardless of the test procedure used. With one exception, sera from control patients were negative or were positive only in sera containing rheumatoid factor. Latex agglutination tests for Candida spp. in treated serum may prove to be a useful procedure for the rapid diagnosis of severe disseminated candidiasis.
Selective reactivity of antibodies to human immunoglobulins G, M, and A with rubella virus proteins
Authors: Partanen P , Seppänen H , Suni J , Vaheri A
Published: January 2020

Proteins of purified rubella virus were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and immunoblotted with human sera and immunoglobulin class heavy-chain-specific peroxidase conjugates. The levels of rubella antibodies in these sera were predetermined by the radial hemolysis test, the density gradient centrifugation method for immunoglobulin M (IgM) antibodies, and IgG-, IgM-, and IgA-specific enzyme immunoassays. In immunoblotting, rubella-specific IgG antibodies reacted with both envelope glycoproteins (E1 and E2) and the capsid protein (C). In contrast, rubella IgM antibodies reacted predominantly with E1, whereas the specific reactivity of IgA antibodies was directed mainly to the capsid protein. Purified IgM rheumatoid factor added to IgG-positive, IgM-negative serum did not give false-positive reactivity in the immunoblotting test as it did in solid-phase enzyme immunoassays. The immunoglobulin class-specific reactivities with the different viral proteins are expected to have diagnostic applications.
Bacterial interactions in bovine respiratory and reproductive infections
Authors: Corbeil L B , Woodward W , Ward A C , Mickelsen W D , Paisley L
Published: January 2020

The ability of the aerobic bacterial flora from the normal bovine respiratory and reproductive tracts to enhance or inhibit the growth of Pasteurella haemolytica, P. multocida, and Haemophilus somnus was tested in vitro. Six strains of each of these pathogens were cross streaked with each isolate of bovine normal flora. Flora which enhanced the growth of these pathogenic bacteria outnumbered inhibitors four to one. An intermediate number of isolates produced no effect on pathogen growth. Most enhancers were gram positive (Micrococcus, Staphylococcus, Corynebacterium, or Rhodococcus isolates), although several isolates of Moraxella and Actinobacter were also good enhancers. For H. somnus, there were proportionally more organisms which produced marked enhancement among the preputial flora than among the nasal flora, which may account for the greater number of genital carriers than nasal carriers. Bacillus isolates were the most significant inhibitors among the nasal flora, whereas no genus or species from the reproductive tract was noted to produce appreciable inhibition. It is proposed that changes in ratios of inhibitors to enhancers may determine, in part, whether a carrier state or disease occurs. Also, suggestions are made for in vitro use of this phenomenon for diagnostic tests.
Laboratory evaluation of leukocyte esterase and nitrite tests for the detection of bacteriuria
Authors: Pfaller M A , Koontz F P
Published: January 2020

We compared the sensitivity, specificity, and predictive values of the 1-min leukocyte esterase test and the test for urinary nitrite alone and in combination as screening tests for bacteriuria in over 5,000 clinical urine specimens. The leukocyte esterase-nitrite combination had a sensitivity of 79.2%, a specificity of 81%, and a negative predictive value of a negative test of 94.5% for specimens with greater than or equal to 10(5) CFU/ml. Although the sensitivity of this test was too low to allow its use as the only screening test for bacteriuria, it may serve as a useful adjunct to culturing and other urine-processing systems in the microbiology laboratory.
In vitro detection of porcine rotavirus-like virus (group B rotavirus) and its antibody
Authors: Theil K W , Saif L J
Published: January 2020

Four isolates of porcine rotavirus-like virus (PRVLV) infected MA104 cells and induced syncytium formation after low-speed centrifugation of the inoculum onto the monolayer. Ten of 44 (23%) Ohio swine sera had PRVLV antibodies when tested by indirect immunofluorescence, using PRVLV-infected MA104 cell monolayers as antigen.
Development of subtype-specific and heterosubtypic antibodies to the influenza A virus hemagglutinin after primary infection in children
Authors: Burlington D B , Wright P F , van Wyke K L , Phelan M A , Mayner R E , Murphy B R
Published: January 2020

Children undergoing primary infection with an H1N1 or H3N2 influenza A virus developed subtype-specific hemagglutination inhibition antibodies and enzyme-linked immunosorbent assay antibodies to purified hemagglutinin (HA) of the infecting virus subtype. They also developed lower titered ELISA antibodies to the noninfecting H1 or H3 HA and to H8 (an avian strain) HA. Thus, after primary infection with an influenza A virus, children develop enzyme-linked immunosorbent assay, but not hemagglutination inhibition, antibodies reactive with heterosubtypic HAs. These heterosubtypic antibodies could influence the response to infection with other wild-type or attenuated vaccine strains of influenza A virus.
Assignment of Actinomyces viscosus and Actinomyces naeslundii strains to numerical taxonomy clusters by immunofluorescence based on antifibril antisera
Authors: Ellen R P , Grove D A
Published: January 2020

A previous observation, using a few representative laboratory strains, that rabbit antisera raised against isolated surface fibrils might be useful in identifying Actinomyces viscosus and Actinomyces naeslundii isolates to their correct numerical taxonomy clusters was reexamined with a large culture collection, including clinical isolates from three different laboratories. Strains were first identified by a slower standard procedure, including agglutination with anti-whole-cell antisera, catalase test, and gas and paper chromatography as needed. Indirect immunofluorescence tests indicated that antisera raised against fibrils of strains representing the three principal taxonomic clusters could separate most strains into their correct clusters. The antisera were particularly successful in separating two taxonomically distinct groups of A. naeslundii, clusters 3 and 5, but could not separate A. viscosus belonging to the principal cluster (no. 1) and minor clusters (no. 2, 4, 6).
Rapid enzyme system for the identification of pathogenic Neisseria spp
Authors: Brown J D , Thomas K R
Published: January 2020

Gonochek II is a combination of three enzyme substrates in one tube which will give a rapid identification (30 min) of those pathogenic Neisseria spp. which can be isolated on Thayer Martin or similar selective media. Eighty isolates were tested by Gonochek II and a carbohydrate utilization method; total agreement was achieved between the two methods.
Alternate radiolabeled markers for detecting metabolic activity of Mycobacterium leprae residing in murine macrophages
Authors: Prasad H K , Hastings R C
Published: January 2020

This study demonstrated the utility of using 4% NaOH as a murine macrophage cell-solubilizing agent to discriminate between host macrophage metabolism and that of intracellular Mycobacterium leprae. A 4% concentration of NaOH had no deleterious effect on labeled mycobacteria. Thereby, alternate radiolabeled indicators of the metabolic activity of intracellular M. leprae could be experimented with. Significant incorporation of 14C-amino acid mixture, [14C]leucine, [14C]uridine, and carrier-free 32P was observed in cultures containing freshly extracted ("live") strains of M. leprae as compared with control cultures containing autoclaved bacilli.
Evidence for limited humoral immunoglobulin M antibody response to hepatitis B core antigen during acute and chronic hepatitis B virus infections
Authors: Lindenschmidt E G , Granato C H , Kätzner K , Laufs R
Published: January 2020

The periods of persisting immunoglobulin M class antibodies to hepatitis B core antigen in 28 patients with acute hepatitis B infections and in 134 patients with chronic hepatitis B infections were studied by using an enzyme-linked immunosorbent assay and an indirect immunofluorescence technique. We showed that the clearance of antibodies to hepatitis B core antigen is independent of the degree of viremia in both forms of hepatitis.
Accuracy and reproducibility of a four-hour method for anaerobe identification
Authors: Appelbaum P C , Kaufmann C S , Depenbusch J W
Published: January 2020

In this study, we evaluated the ability of a 4-h enzyme assay kit system, the RapID ANA method (Innovative Diagnostic Systems, Inc., Atlanta, Ga.) to accurately and reproducibly identify a spectrum of clinically significant anaerobic bacteria in two separate institutions. Additional tests were performed as required. Of a total of 188 organisms tested at Hershey Medical Center (HMC), 86.2% were correctly identified to species level without additional tests, 5.9% required extra tests for correct identification, and 8.0% were misidentified. Of 53 strains tested at Johns Hopkins Hospital (JHH), 52.8% were correctly identified without extra tests, 28.3% required extra tests for correct identification, and 18.9% were misidentified. Of 21 organisms tested at both institutions, those tested at JHH required additional tests for correct identification in 38.1% of cases, compared with 9.5% at HMC. Misidentification rates were identical (9.5%) in both centers. Of strains tested at HMC only, 86.8% were correctly identified without extra tests, 5.4% were identified with additional tests, and 7.8% were misidentified: corresponding data for JHH were 53.1, 21.9, and 25.0%, respectively. Of 53 strains tested in triplicate at JHH, 56.7% yielded the same result on each occasion, 37.7% were identical in two of three tests, and 5.7% gave different results on each of three occasions. Discrepancies between identification rates at HMC and JHH may be explained by differences in species tested (more commonly encountered species were tested at HMC) and interpretation of reactions by the two different readers. The RapID ANA method has the potential for rapid identification of clinically isolated anaerobes; however, accuracy and reproducibility may vary as a function of the specific laboratory setting.
Radioimmunoassays for the detection of antibodies to treponemal polypeptide antigens in serum
Authors: Baughn R E , Musher D M
Published: January 2020

Cross-reacting treponemal antigens are potentially important candidates for serodiagnostic assays in syphilitic infections. Based on the idea that the organelles for locomotion in virulent and avirulent treponemes might be composed of similar subunits, we attempted to purify the flagellar antigens of Treponema phagedenis biotype Reiter and Treponema refringens for use in radioimmunoassays. With a combination of physical and chemical methods, the major protein subunit of purified flagellar preparations exhibited a mass of approximately 37 kilodaltons (kd) on sodium dodecyl sulfate-polyacrylamide gels. These 37-kd materials, with weight estimates comparable to those of other flagellin molecules, were further purified by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electroelution. Human and rabbit sera, alone or subjected to DEAE Affi-Gel blue chromatography, were subsequently tested in radioimmunoassays employing each of the purified preparations. Even though sera from patients with secondary syphilis and from experimentally infected animals at 3 to 4 weeks postinfection were reactive in radioimmunoassays employing the 37-kd flagellar antigens, the assays were relatively insensitive for detection of immunoglobulin G responses in the early stages of human infection. Detection of immunoglobulin G antibodies in sera obtained early in the course of natural or experimental infection was possible with electroeluted 33- to 64-kd materials from both avirulent and virulent treponemes.
Effect of delay in processing on the performance of Directigen for the detection of group A streptococci in throat swabs
Authors: Matteson M L , Anhalt J P
Published: January 2020

We compared a latex agglutination method, Directigen (Hynson, Westcott & Dunning) with a culture-based system for detection of group A streptococci in 964 throat swabs. Discordants were resolved by Lancefield typing of beta-hemolytic colonies. After culture, swabs were randomly assigned to be tested by Directigen within 4 h of sampling or after overnight storage. For swabs that yielded more than 50 beta-hemolytic colonies from culture, there was a highly significant difference (P less than 0.01) in sensitivity between the group tested early and the group tested after storage overnight. For swabs tested within 4 h of sampling, a trend (P = 0.07) existed between sensitivity and length of delay before testing.
Comparative evaluation of five commercial systems for the rapid identification of pathogenic Neisseria species
Authors: Philip A , Garton G C
Published: January 2020

Prompt diagnosis and effective treatment of urogenital gonococcal infections require rapid isolation and identification of Neisseria gonorrhoeae from urogenital specimens. We evaluated a new, rapid (30-min) test called Gonochek II (E-Y Laboratories, San Mateo, Calif.) which utilizes chromogenic substrates for the identification of pathogenic Neisseria species. It was compared with the API NeIdent (Analytab Products, Inc., Plainview, N.Y.), Minitek (BBL Microbiology Systems, Cockeysville, Md.), and RapID NH (Innovative Diagnostics, Atlanta, Ga.), systems and the Phadebact GC (Pharmacia Diagnostics, Piscataway, N.J.) test for its performance in identifying known strains of N. gonorrhoeae (39 strains), Neisseria meningitidis (22 strains), Neisseria lactamica (12 strains), and Branhamella catarrhalis (17 strains). The Gonochek II system correctly identified 100% of N. gonorrhoeae, N. lactamica, and B. catarrhalis strains and 95.4% of N. meningitidis strains. The percent agreement for correct identification of all strains tested was 98.8%. In contrast, the Minitek, RapID NH, and API NeIdent systems correctly identified 86.6, 80.0, and 73.3% of the strains, respectively. The Phadebact GC test identified 94.9% of the N. gonorrhoeae isolates but also cross-reacted with 41.6% of the N. lactamica strains. The Gonochek II system is rapid, simple to perform, and easy to interpret, requires 1 to 2 min to set up, and more accurately identifies pathogenic Neisseria species when compared with other systems used in this study.
In vitro assessment of virulence in Yersinia enterocolitica and related species
Authors: Prpic J K , Robins-Browne R M , Davey R B
Published: January 2020

We have examined 136 isolates of Yersinia species, comprising 112 strains of Yersinia enterocolitica, 12 of Y. frederiksenii, 8 of Y. intermedia, and 5 of Y. kristensenii, for the presence of 40- to 50-megadalton virulence-associated plasmids and expression of the following plasmid-associated characteristics: Congo red pigmentation (CR), calcium dependence, autoagglutination, hydrophobicity, resistance to normal human serum, and pathogenicity in mice. All 136 strains yielded both pigmented (CR+) and nonpigmented (CR-) variants. Only CR+ variants, however, were virulent for iron-overloaded, desferrioxamine B-treated mice (R. M. Robins-Browne and J. K. Prpic, Infect. Immun. 47:744-779, 1985). Although the in vitro virulence-associated characteristics generally occurred together, each one could be expressed independently. Strains of Y. frederiksenii, Y. intermedia, and Y. kristensenii also expressed individual virulence-associated properties. Of 53 Y. enterocolitica strains which were virulent for iron-overloaded, desferrioxamine-treated mice, all but one expressed every virulence-associated characteristic. Several strains which were avirulent for mice, however, demonstrated these characteristics in various combinations. Because many Yersinia strains, particularly environmental isolates, carried plasmids of 40 to 50 megadaltons, detection of plasmids provided little information about bacterial pathogenicity unless virulence-associated properties were also sought. The best in vitro predictor of virulence was autoagglutination, followed by calcium dependence. Because only CR+ variants expressed virulence-associated determinants, Congo red pigmentation is useful for selecting potentially virulent strains.
Development of a bacteriophage typing system for Campylobacter jejuni and Campylobacter coli
Authors: Grajewski B A , Kusek J W , Gelfand H M
Published: January 2020

A bacteriophage typing system for Campylobacter jejuni and Campylobacter coli was developed with phages isolated from poultry feces. Data for phage selection were generated from a set of isolates of C. jejuni and C. coli from humans in Illinois. Selection of 14 phages from the 47 phages available was assisted by determination of the Sneath-Jaccard similarity coefficients and subsequent unweighted pair-group arithmetic averaging cluster analysis. The typing set was reproducible and stable in the 255 isolates from Illinois. Of these isolates, 94.5% were typable, with 46% represented by the four most common phage patterns. In a set of 51 isolates from humans outside of Illinois, 88.1% of the C. jejuni isolates were typable. Phage typing for C. jejuni and C. coli has excellent epidemiologic potential and should serve as a useful adjunct or alternative to serotyping systems in current use.
Interaction of Campylobacter jejuni and Campylobacter coli with lectins and blood group antibodies
Authors: Wong K H , Skelton S K , Feeley J C
Published: January 2020

Lectins and blood group antibodies were used to probe the surface structures of Campylobacter jejuni and Campylobacter coli. Of the 29 strains tested, there were distinct reaction patterns. The lectin-reactive and blood group antibody-reactive sites on the bacterial surface were distinguishable from the heat-stable (lipopolysaccharide) antigenic determinants. The interactions were strain specific. The reactive sites were stable with respect to culture media and passage and may be useful as additional markers for strain characterization.
Invasiveness of Aeromonas spp. in relation to biotype, virulence factors, and clinical features
Authors: Watson I M , Robinson J O , Burke V , Gracey M
Published: January 2020

Of 69 fecal isolates of Aeromonas spp., 18 had the ability to invade HEp-2 cells. Invasiveness correlated with biotype; of the 18 invasive strains, 16 were A. sobria and 2 were A. hydrophila. No invasive strains were found among the A. caviae. Of the 18 invasive strains, 13 were enterotoxigenic. Of the enterotoxigenic and invasive strains, 12 were A. sobria, but enterotoxicity was also more common among noninvasive strains of A. sobria. Fucose-resistant hemagglutination was also more common in A. sobria, but invasive strains were equally divided between fucose-resistant hemagglutination and other patterns. Detailed clinical information was available for 27 of the 69 strains. All 15 strains of A. sobria or A. hydrophila associated with diarrhea were enterotoxigenic; 6 of the 10 strains of A. sobria were also invasive. Blood was present in the stool samples of five of the six patients with invasive A. sobria and in none of the patients with noninvasive strains. Although limited, these observations suggest that dysenteric symptoms may be produced by invasive Aeromonas spp.
DNA relatedness and biochemical features of Campylobacter spp. isolated in central and South Australia
Authors: Steele T W , Sangster N , Lanser J A
Published: January 2020

Investigations of the etiology of diarrhea in patients in South Australia and the Northern Territory showed that Campylobacter spp. other than Campylobacter jejuni and C. coli were common in children. Campylobacters which were hippurate positive, nitrate negative, and susceptible to cephalothin and polymyxins were shown to be closely related to C. jejuni by DNA studies. Thermotolerant catalase-negative campylobacters were also isolated. These were H2S negative and biochemically resembled the catalase-negative or weak strains found in dogs in Sweden. DNA studies showed these campylobacters to be distinct from C. sputorum subsp. sputorum and to form a homogeneous group distinct from the enteropathogenic catalase-positive campylobacters. Preliminary studies suggest that these campylobacters are related to the Swedish catalase-negative or weak strains.
Mycobacterium avium complex, an emerging pathogen in Massachusetts
Authors: du Moulin G C , Sherman I H , Hoaglin D C , Stottmeier K D
Published: January 2020

We report a study of 1,953 patients whose laboratory records from 1972 through 1983 at the Massachusetts Mycobacteria Reference Laboratory indicated the isolation of Mycobacterium avium complex (MAC) organisms. At least one clinical specimen from each patient during this period exhibited the organism. The incidence of isolation of MAC has increased fivefold since 1972, with a doubling of the number of patients with positive MAC specimens from normally sterile sites occurring since 1980. A concomitant increase of more than fourfold in other nontuberculous mycobacteria has occurred. Most isolates came from high-density population centers. Communities whose drinking water comes from a distant rather than a local source were more likely to have patients with MAC.
Double immunofluorescence microscopic technique for accurate differentiation of extracellularly and intracellularly located bacteria in cell culture
Authors: Heesemann J , Laufs R
Published: January 2020

A double immunofluorescence staining technique is described for differentiation between cell-attached (extracellular) and ingested (intracellular) bacteria by HEp-2 cells in cell culture monolayers. This method is based upon the observation that membranes of viable mammalian cells are impermeable for antibodies but are rendered permeable by treatment with fixatives. Consequently, extracellular bacteria can be stained by specific rhodamine-labeled antibodies before fixation, and intracellular bacteria can be visualized by treatment with specific fluorescein-labeled antibodies after fixation. The accuracy and simplicity of this method is demonstrated with HEp-2 cell culture monolayers as target cells and an isogenic pair of Yersinia enterocolitica, one of which is phagocytosis resistant and the other of which is phagocytosis sensitive. Furthermore, it is shown that this staining technique is also applicable for studying the interaction of bacteria with macrophages and fibroblasts.
Serum susceptibility of Haemophilus somnus from bovine clinical cases and carriers
Authors: Corbeil L B , Blau K , Prieur D J , Ward A C
Published: January 2020

The serum susceptibility of 64 isolates of Haemophilus somnus from cattle was determined in a bactericidal assay with undiluted fresh or inactivated bovine serum with serial dilutions of bacterial suspension in RPMI 1640 medium. A total of 27 strains isolated from cattle with clinical disease (4 with thromboembolic meningoencephalitis, 13 with pneumonia, and 10 with reproductive failure) were compared with 35 strains from asymptomatic carriers (11 from the vagina and 24 from the prepuce). Essentially, all clinical isolates were serum resistant, whereas approximately 25% of preputial isolates were serum susceptible, as judged after 1 h of incubation in serum; a majority of vaginal isolates showed delayed serum susceptibility. Lysozyme played no role in serum killing, and the alternative complement pathway played only a minor role. Iron saturation, however, appeared to impart greater serum resistance to serum-susceptible strains from the vagina and prepuce. Perhaps the serum-susceptible strains from carriers would be useful vaccine candidates, but resistant strains from carriers may be pathogenic.