bluuebunny/crossref_metadata_2025 huggingface dataset:
Serological classification of Achromobacter xylosoxidans
Authors: Shigeta S , Hyodo S , Chonan E , Yabuuchi E
Published: January 2020

Adult rabbits were immunized with nine Achromobacter xylosoxidans strains by intravenous injection of Formalin-killed organisms. Antisera thus obtained were reciprocally titrated with the nine A. xylosoxidans strains, and seven sera were defined as serologically distinct. Three of nine antisera possessed one common antibody while also each having their own specific antibody. Ninety-five strains of A. xylosoxidans were examined for serotyping by a microtiter agglutination test with the nine antisera, and the strains were divided into seven serogroups. The distribution of the 95 strains among the serogroups was as follows: serogroup A, 15 strains; B, 17 strains; C, 43 strains; D, 2 strains; E, 4 strains; G, 8 strains; F, 2 strains. Four strains were not agglutinated with any of the antisera. Serogroups A, B, and F had the ability to reduce nitrate to nitrogen gas and to grow in heart infusion broth at 41 degrees C, although there were some exceptions. In contrast, most strains of serogroups C, D, and E could not produce nitrogen gas from nitrate, although they did produce nitrite. The strains of serogroup C could not grow at 41 degrees C, whereas those of serogroups D and E could. Thus, we concluded that serogroups A, B, and F referred to biotype IIIb described by Tatum, and serogroups C, D, and E referred to biotype IIIa. The serotyping of A. xylosoxidans may be useful for the analysis of nosocomial infections caused by these organisms.
Reduced set of phages for typing salmonellae
Authors: Gershman M , Markowsky G
Published: January 2020

A set composed of 27 phages is described for differentiating Salmonella spp. representative of groups A, B, C1, C2, D1, D2, E1, E2, E3, E4, G1, K, and N. All of the 1,245 cultures used in this effort were typable and were differentiated on the basis of the 420 phage patterns observed. All results were reproducible. Characteristic phage patterns were produced by a variety of Salmonella serovars isolated from campus incidents and a number of hospital, family, restaurant, and processing plant outbreaks to indicate an existing epidemiological relationship.
Comparison of a new rapid plasma reagin card test with the standard rapid plasma reagin 18-mm circle card test and the venereal disease research laboratory slide test for serodiagnosis of syphilis
Authors: Hambie E A , Larsen S A , Perryman M W , Pettit D E , Mullally R L , Whittington W
Published: January 2020

The rapid plasma reagin (RPR) card test manufactured by Beckman Instruments, Inc., was compared, qualitatively and quantitatively, with the Venereal Disease Research Laboratory (VDRL) slide test and the standard RPR 18-mm circle card tests for the serodiagnosis of syphilis. Sera from 638 individuals were used in this study. Two pilot lots and two production lots of antigen were submitted by Beckman Instruments, Inc., for evaluation. Qualitative agreement among the three RPR card tests was 98.1%; between the Beckman RPR card and the VDRL slide tests, 95.0%; and between the reference RPR card and the VDRL slide tests, 95.5%. The Beckman RPR card test was 95.3% specific, whereas the specificities of the reference RPR card and the VDRL slide tests were 98.8% and 96.1%, respectively. Sensitivities of the three nontreponemal tests were: Beckman RPR card test production lots, 94.7%; reference RPR card test, 96.8%; and VDRL slide test, 90.6%. Quantitative agreement +/- 1 dilution among the three RPR card tests was 93.0%, whereas quantitative agreement was approximately 40% when both RPR card tests were compared with the VDRL slide test. We found the Beckman RPR card test comparable to the standard RPR card tests. Therefore, the decision of which test to use for the serodiagnosis of syphilis is at the discretion of the user.
Gas-chromatographic detection of urinary tract infections caused by Escherichia coli and Klebsiella sp
Authors: Manja K S , Rao K M
Published: January 2020

A gas-chromatographic method for the diagnosis of urinary tract infections caused by Escherichia coli and Klebsiella sp. is described. A total of 96 urine samples from individuals with clinical symptoms of urinary tract infection or pyrexia of unknown origin were tested by conventional and gas-chromatographic methods for bacteriuria. The gas-chromatographic method showed complete agreement with the conventional method in diagnosing all of 16 cases of bacteriuria caused by E. coli and 4 cases caused by Klebsiella sp. The remaining two cases of bacteriuria, caused by other bacteria, were not detected by the gas-chromatographic method.
Characterization of coagulase-negative staphylococci from urinary tract specimens
Authors: Nicolle L E , Hoban S A , Harding G K
Published: January 2020

Species of coagulase-negative staphylococci isolated from urine specimens submitted from both inpatients and outpatients to the clinical microbiology laboratory of a teaching hospital were identified with a biotyping system, with species then correlated by clinical features and antimicrobial susceptibility. Of 145 isolates, 102 (70%) were Staphylococcus epidermidis, 24 (17%) were Staphylococcus saprophyticus, 7 (4.7%) were Staphylococcus haemolyticus, 4 (2.8%) were Staphylococcus hominis, 3 (2.1%) were Staphylococcus simulans, and 5 (3.4%) were other species. Features characterizing persons with bacteriuria with S. saprophyticus compared with bacteriuria with any other species included female sex (95% versus 52%), young age (median age, 22 years versus 61 years), ambulatory status (hospital outpatients, 86% versus 23%), and absence of indwelling catheters (4.5% versus 49%). All other coagulase-negative staphylococci were isolated in a setting suggesting nosocomial acquisition, were more frequently resistant to common antimicrobial agents (42% multiply resistant versus 4.2% of S. saprophyticus), and were not distinguished by clinical features. Novobiocin susceptibility, with a sensitivity of 100% and specificity of 96%, provided a simple and reliable test for differentiation of S. saprophyticus from other coagulase-negative staphylococci and should be routinely used for urinary tract specimens in the clinical laboratory.
Rapid diagnosis of varicella-zoster virus infection by detection of viral deoxythymidine kinase in serum and vesicle fluid
Authors: Källander C F , Gronowitz J S , Olding-Stenkvist E
Published: January 2020

A sensitive enzyme assay utilizing [125I]iododeoxyuridine as the substrate and CTP as the phosphate donor in combination with isozyme-specific antisera was used for direct detection and typing of herpesvirus deoxythymidine kinase (dTk) in clinical specimens. An investigation of 16 coded vesicle fluid specimens, taken in connection with varicella-zoster virus (VZV) and herpes simplex virus infections, revealed viral dTk activity in 14 samples. All positive samples except one were taken within 5 days after the onset of illness. Serological typing of the dTk activities easily established whether the vesicles were caused by VZV, herpes simplex virus type 1, or herpes simplex virus type 2. The results were obtainable within 5 h and were in agreement with the results achieved by immunofluorescence tests or by virus isolation when positive. Acute- and convalescent-phase sera from patients with VZV infections were analyzed with regard to dTk isozyme composition. All sera collected within 5 days after the onset of varicella were found to contain elevated levels of dTk activity. By the use of isozyme-specific antisera and gel electrophoresis, it was possible to show the presence of both cellular and VZV dTk's. Among the 13 acute-phase sera from zoster patients, only 2 were found to be VZV dTk positive. Convalescent sera, in most cases collected 15 days or more after the onset of illness, were also found to be devoid of VZV dTk. The relevance of the results and the possible use of these methods for viral diagnostics are discussed.
Comparative evaluation of the micro-media system, sceptor, and MIC-2000 microdilution methods for testing Pseudomonas aeruginosa against gentamicin, tobramycin, and amikacin
Authors: Woolfrey B F , Lally R T , Quall C O
Published: January 2020

Minimum inhibitory concentrations (MICs) for selected strains of Pseudomonas aeruginosa versus gentamicin, tobramycin, and amikacin were replicated in parallel with MMS (Micro-Media Systems, Potomac, Md). Sceptor (BBL Microbiology Systems, Cockeysville, Md), and matching MIC-2000 (Dynatech Laboratories, Inc., Alexandria, Va.) twofold dilution panels and with MIC-2000 panels with dilutions differing by small arithmetic increments. The three microdilution systems produced comparable modal MICs. However, dispersion about modal values was greater for MMS than for either Sceptor or comparable MIC-2000 twofold panels. MICs were best define by MIC-2000 panels with dilutions differing by small arithmetic increments, for which 72.9% of MICs were modal, 95.4% were one small increment step or less from the modal value, and 100% were two small-increment steps or less form the modal value. The similarity of MIC replication for Sceptor and MIC-2000 twofold panels suggests the possibility of using small increment dilutions by Sceptor.
Affinity purification of bovine antibodies to Brucella abortus Lipopolysaccharide
Authors: Stiller J M , Nielsen K H
Published: January 2020

Alkali-treated lipopolysaccharide from Brucella abortus S1119.3 coupled to agarose beads by cyanogen bromide activation resulted in an immunoadsorbent with which a large amount of B. abortus-specific antibodies could be purified. The method described gave alkali-treated lipopolysaccharide binding efficiencies of up to 98%. There was little loss of alkali-treated lipopolysaccharide from the column after several pH shifts, allowing the immunoadsorbent to be regenerated and used repeatedly.
Comparison of the B-D urine culture kit with a standard culture method and with the MS-2
Authors: Hubbard W A , Shalis P J , McClatchey K D
Published: January 2020

A total of 100 random clinical urine specimens were divided and used to compare Becton, Dickinson & Co. B-D Urine Culture Kit-treated urine (BDU) with refrigerated urine (RU). Each RU-BDU pair was cultured with the standard calibrated loop-plate method and also screened with the Abbott Laboratories MS-2 system at 0, 5, and 24 h. An additional 158 positive urine specimens containing greater than 10(5) CFU/ml were tested by standard culturing and MS-2 at 0 and 24 h. In addition, growth curves were run for Escherichia coli containing RU-BDU pairs at 0 and 24 h, and MS-2 detection time frequencies were analyzed. Culture results showed few changes in colony counts at 0 and 5 h for RU and BDU specimens. At 24 h, there were decreased colony counts for 7.0% of RU and 17.7% of BDU specimens. MS-2 results showed detection rates at 0 h of 100% for RU and 82.9% for BDU specimens and at 24 h of 91.1% for RU and 63.3% for BDU specimens. The organisms most frequently missed at 24 h were E. coli, Pseudomonas aeruginosa, and Staphylococcus epidermidis. Growth curve analysis showed a 1-h delay of logarithmic growth in BDU specimens. MS-2 detection time analysis showed delayed positive reports owing to be extended detection time for BDU specimens. The B-D Urine Culture Kit is a convenient transport system; however, some difficulty in recovering organisms at 24 h with the standard culture method and increased difficulty with the MS-2 system were recognized.
Effect of atmosphere and duration of incubation on primary isolation of group A streptococci from throat cultures
Authors: Lauer B A , Reller L B , Mirrett S
Published: January 2020

The optimal incubation conditions for isolation of group A streptococci from throat cultures are controversial. Therefore, we compared the effects of aerobic and anaerobic incubations after 24 and 48 h on the recovery of group A streptococci. Throat swabs submitted to the clinical laboratory were inoculated onto duplicate 5% sheep blood agar plates, incubated aerobically or anaerobically (GasPak jar) at 35 degrees C, and examined semiquantitatively after 24 and 48 h. Group A streptococci were identified by the fluorescent-antibody technique. Of 1,040 specimens, 506 (48.6%) grew beta-hemolytic streptococci, including 200 (19.2%) group A streptococci. Group A streptococci were recovered significantly more often with anaerobic incubation than with aerobic incubation after 24 h (182 versus 138; P less than 0.001) and after 48 h (193 versus 174; P less than 0.05). Non-group A beta-hemolytic streptococci also were recovered significantly more often with anaerobic incubation after 24 and 48 h (P less than 0.001). Colony counts were not affected by the incubation atmosphere. We conclude that incubation of throat cultures in an anaerobic atmosphere is superior to incubation in air for detection of group A streptococci. The greater sensitivity of anaerobic incubation, however, may not justify the extra laboratory effort and cost required to differentiate group A streptococci from the non-group A streptococci detected as a result of anaerobic incubation. Throat cultures should be examined after 24 and 48 h, especially if plates are incubated aerobically.
EDTA-treated plasma in the rapid plasma reagin card test and the toluidine red unheated serum test for serodiagnosis of syphilis
Authors: Larsen S A , Pettit D E , Perryman M W , Hambie E A , Mullally R , Whittington W
Published: January 2020

Both the rapid plasma reagin (RPR) 18-mm circle card test and the toluidine red unheated serum test (TRUST) were designed to be more rapid than the Venereal Disease Research Laboratory slide test for the serodiagnosis of syphilis. The RPR card test, although originally designed as the teardrop card test for use with plasma, has received recognition from the Centers for Disease Control as a standard test for syphilis for use with serum samples only. In this study, 132 EDTA plasma-serum pairs were tested in both the RPR card test and TRUST immediately after the blood was drawn and the serum or plasma was separated from the cellular constituents of the blood. The plasma samples were further tested at 24-h intervals of storage at 25 and 4 degrees C for 72 h. Special attention was paid to any increase in roughness in nonreactive specimens. The greatest increase in roughness (16.7%) was seen with the TRUST after 72 h at 25 degrees C. An additional 174 plasma-serum pairs were tested after 18 h of storage at 25 degrees C. Comparisons of the results of the 306 serum specimens with their corresponding plasma pairs gave 99.0% qualitative agreement for both tests. Quantitative agreement +/- 1 dilution between serum-plasma pairs tested within 18 h was 92.1% (35 of 38) for the RPR card test and 94.1% (32 of 34) for the TRUST. Our results with plasma from blood drawn with EDTA as the anticoagulant were comparable with results with serum specimens for both tests when plasma specimens were tested within 18 to 24 h.
Rapid identification of enterococci
Authors: Brown L H , Peterson E M , de la Maza L M
Published: January 2020

Enterococci were identified in 4 h with bile esculin agar and the Autobac system (General Diagnostics, Warner-Lambert Co., Morris Plains, N.J.), which was used to incubate and monitor salt broth for growth. Of 86 group D streptococci tested, 41 enterococci grew in salt broth and were bile esculin positive within 4 h; none of 45 group D nonenterococcal streptococci exhibited growth in the salt broth, and only 38 of them were bile esculin positive within 4 h.
Multidose vials versus single-dose vials: a study in sterility and cost-effectiveness
Authors: Sheth N K , Post G T , Wisniewski T R , Uttech B V
Published: January 2020

A total of 197 multidose injectable vials were collected from 10 different nursing stations and evaluated for sterility. Experimental contamination studies were undertaken, and the cost-effectiveness of multidose vials was compared with that of single-dose vials. Our results showed that bacterial contamination of multidose injectable vials was not a significant hazard; in addition, contrary to common belief, the use of multidose vials was not always successful as a cost-containment measure.
Comparison of biological, biochemical, immunological, and immunochemical techniques for typing herpes simplex virus isolates
Authors: Zheng Z M , Mayo D R , Hsiung G D
Published: January 2020

In this study, 102 herpes simplex virus isolates were typed by cell culture selection (chicken embryo cells and guinea pig embryo cells [CE/GPE]), (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) sensitivity, plaque reduction neutralization, and indirect immunofluorescence staining techniques. The percentages of agreement between the typing methods were as follows: BVDU sensitivity versus CE/GPE, 99% (99/102); CE/GPE and BVDU sensitivity versus neutralization, 32% (33/102); CE/GPE and BVDU sensitivity versus indirect immunofluorescence staining 17% (17/102). Results were easy to interpret when the CE/GPE and BVDU sensitivity systems were used. In contrast, when type-specific antisera prepared commercially were used, results were often obscure, even contradictory, because of antibody cross-reactions. Therefore, this study suggests that immunological and immunochemical methods that use presently available commercially prepared antisera cannot reliably differentiate herpes simplex virus type 1 from type 2.
Reactivity of microhemagglutination, fluorescent treponemal antibody absorption, Venereal Disease Research Laboratory, and rapid plasma reagin tests in primary syphilis
Authors: Huber T W , Storms S , Young P , Phillips L E , Rogers T E , Moore D G , Williams R P
Published: January 2020

Seroreactivity of sera from 109 patients with first-infection primary syphilis was 98.2% in the fluorescent treponemal antibody absorption test, 92.7% in the rapid plasma reagin 18-mm circle card test, 72.5% in the microhemagglutination test (MHA-TP), and 72.5% in the Venereal Disease Research Laboratory test. Seroreactivity of sera from 18 patients with primary syphilis with documented previous infection(s) was 100% in the fluorescent treponemal antibody absorption test, the rapid plasma reagin 18-mm circle card test, and the MHA-TP test and 88.9% in the Venereal Disease Research Laboratory test. The MHA-TP test failed to confirm reactivity in 13 of 79 sera which were reactive in the Venereal Disease Research Laboratory test and in 24 of 101 sera which were reactive in the rapid plasma reagin 18-mm circle card test. Testing another production lot of MHA-TP reagents resulted in even poorer correlation. The reactivity of the MHA-TP test in primary syphilis appeared to vary with the sensitivity of the production lot of reagents.
Association of iota-like toxin and Clostridium spiroforme with both spontaneous and antibiotic-associated diarrhea and colitis in rabbits
Authors: Borriello S P , Carman R J
Published: January 2020

A helically coiled, anaerobic, gram-positive sporeforming bacillus, identified as Clostridium spiroforme, was isolated from the cecal contents of all of 27 rabbits with spontaneous diarrhea, at a mean concentration of 10(6.0) spores per g of material. All of these rabbits also had a toxin present in their cecal contents that was neutralized by anti-Clostridium perfringens type E iota toxin, but not by other clostridial antitoxins. In addition, four rabbits with clindamycin-associated colitis were positive for C. spiroforme at a mean concentration of 10(4.5). All of these animals also had iota-like toxin present. Iota-like toxin was not detected in the cecal contents of 72 healthy animals, although C. spiroforme was found in two of these animals at a mean concentration of 10(6.0). C. spiroforme was shown to produce a toxin in vitro that was lethal to mice and caused dermonecrosis in guinea pigs. In all cases, this toxin was neutralized by anti-C. perfringens type E iota toxin.
Correlation between biochemical and serological characteristics of Escherichia coli and results of the Serény test
Authors: Toledo M R , Trabulsi L R
Published: January 2020

A total of 1,335 Escherichia coli strains isolated from patients with diarrhea were submitted to the Serény test. Of these strains, 1,035 were also submitted to slide agglutination test, using antisera for invasive E. coli serogroups. Of 325 isolates that were lysine decarboxylase negative, 138 reacted with one of the E. coli antisera used. From this group of 138, 137 were positive in the Serény test. Strains that were lysine decarboxylase positive (1,010 strains) were all negative in the Serény test. These results show a close correlation between the biochemical and serological characteristics of E. coli and the results of the Serény test.
Collaborative evaluation of the microbial profile system for quantitative antimicrobial susceptibility testing
Authors: Gerlach E H , Jones R N , Barry A L
Published: January 2020

This three-center collaborative study was conducted to evaluate samples of the Microbial Profile System (MPS) antimicrobial microdilution panels [previously produced by Minnesota Mining & Manufacturing Co., (3M Co.), St. Paul, Minn. and currently produced by Flow Laboratories, Inc., Rockville, Md.). This was a three-phase study. In phase I, the inter- and intralaboratory agreement was determined by using strains with selected ranges of susceptibility. The MPS and reference microdilution minimum inhibitory concentrations were within acceptable variation, +/- 1 dilution for 97.7% for the MPS and 98.8% for the reference microdilution panels for the intralaboratory comparisons. The percentage of strains with minimum inhibitory concentrations in the acceptable range for the interlaboratory variation was 96.2% for the MPS and 96.0% for the reference microdilution panels. The phase II studies used strains with known resistance mechanisms. The percent agreement with these strains was: Enterobacteriaceae, 94.5%; nonenteric gram-negative rods, 95.4%; staphylococci, 92.3%; and streptococci, 96.6%. The overall agreement within acceptable limits was 94.7% with these strains. When testing 359 clinical isolates, the frequency of strains within the acceptable range of agreement between the two methods was 97.3%. The MPS panels gave results in each of the three study phases equivalent to those obtained with the reference microdilution panels.
Acridine orange staining and radiometric detection of microorganisms in blood cultures
Authors: Burdash N M , Manos J P , Bannister E R , Welborn A L
Published: January 2020

To determine whether acridine orange (AO) staining of blood cultures could be used as a substitute for blind subculture when used in conjunction with the BACTEC system (Johnston Laboratories, Inc., Towson, Md.), the two methods were compared on all BACTEC-negative specimens. Since blind subcultures were routinely performed in our laboratory on days 2 and 6 of incubation, AO staining was also performed on these days. Cultures which were BACTEC positive on day 1 of incubation were not included in the study. Of the 2,395 bottles tested after 2 days of incubation, 106 were subculture positive. Of these, 96 (90.6%) were also AO positive and BACTEC positive, 3 (2.8%) were AO positive and BACTEC negative, and 7 (6.6%) were AO negative and BACTEC positive. Of the 3,487 bottles tested on day 6 of incubation, 14 were subculture positive; 7 (50%) of these were AO positive and BACTEC positive, and seven were AO positive and BACTEC negative. Of the total of 10 culture-positive bottles missed by BACTEC, all were positive, and all 10 companion aerobic bottles were BACTEC positive. In both phases of the experiment, there was a total of only four false-positive AO stains. As a result of this investigation, we have substituted AO staining for blind subculturing of BACTEC-negative bottles.
Biosynthesis of prodigiosin by white strains of Serratia marcescens isolated from patients
Authors: Ding M J , Williams R P
Published: January 2020

Serratia marcescens isolated from infected adults generally does not synthesize prodigiosin. Other investigators have reported that most clinical strains form a pigment if furnished with 4-methoxy-2,2'-bipyrrole-5-carboxyaldehyde (MBC), a precursor of prodigiosin. To determine whether the pigment was prodigiosin, we studied 65 white strains of S. marcescens isolated from patients. On the basis of response to MBC, we assigned the strains to one of three classes: class 1 (14 strains), strains remaining white; class 2 (48 strains), strains becoming gray or pink; and class 3 (3 strains), strains becoming blue. Ethanol extracts of bacteria of classes 2 and 3 did not behave like prodigiosin when acidified or alkalinized, and the pigment spectra were not similar to prodigiosin spectra. If strains of class 3 were furnished with MBC plus 2-methyl-3-amylpyrrole (MAP), the other immediate precursor of prodigiosin, the pigment synthesized was characteristic of prodigiosin. Strains of classes 1 and 2 responded identically to MBC plus MAP and MBC alone. Although the majority of S. marcescens white strains from patients formed pigments in the presence of MBC, the pigments were not prodigiosin. A few strains did synthesize prodigiosin, but only if furnished with both MBC and MAP.
Rapid test for detection of rabies antibodies in human serum
Authors: Budzko D B , Charamella L J , Jelinek D , Anderson G R
Published: January 2020

A simple, sensitive, rapid method based on the principle of immunoadherence hemagglutination (IAHA) has been devised for the detection of rabies antibody. In this test, fixation of complement to complexes of rabies antigen with specific antibodies is readily detected by agglutination of human erythrocytes bearing receptors for C3. Sera from individuals undergoing preexposure rabies immunization were tested for rabies antibodies by the IAHA method and by a virus neutralization test performed in tissue culture, the rapid fluorescent focus inhibition test. IAHA titers showed a high degree of correlation with rapid fluorescent focus inhibition test titers, although it is not known whether results of the IAHA test represent the detection of neutralizing antibodies. An advantage of the IAHA test over the rapid fluorescent focus inhibition test was that results were obtained in a shorter period of time. In some instances, this can be of clinical significance in determining antibody levels to rabies virus. Furthermore, the IAHA test is most applicable as a rapid screening tool for the detection and quantitation of rabies antibodies in vaccinated subjects.
Rapid evaluation of gonococcal and nongonococcal urethritis in men with Limulus amoebocyte lysate and a chromogenic substrate
Authors: Prior R B , Spagna V A
Published: January 2020

A chromogenic substrate was used with Limulus amoebocyte lysate (LAL) and compared by parallel testing with the traditional gelation LAL method for the rapid evaluation of exudative urethritis in 125 male patients. Of these patients, 67 had positive cultures for Neisseria gonorrhoeae and 58 were negative. The corresponding prevalence of gonococcal urethritis was 53.6%. For assay, diluted urethral samples and chromogenic substrate were added directly to single-test LAL vials, and objective color endpoint determinations were made visually after a 10-min incubation period at 37 degrees C. Sensitivity and specificity were 98.5% and 93.1%, respectively, with an overall accuracy in predicting culture results of 96.0%. The predictive value of a positive LAL test was 94.3% in our patient population; in a population with a prevalence of gonococcal urethritis of only 10%, the predictive value would be 61.3%. Results were not statistically different from those obtained by the 30-min gelation LAL method or by Gram-stained smears read by experienced microscopists (P greater than 0.05). Unlike the delicate gel, the color endpoint was not prone to accidental mechanical disruption during incubation or reading. Thus, use of a chromogenic substrate greatly improved the utility and speed of the LAL assay for evaluating men with exudative urethritis while not affecting the accuracy of the test.
Competitive enzyme immunoassay for detection of complement-fixing antibodies in diagnostic virology
Authors: Giunta S , Groppa G
Published: January 2020

A competitive enzyme immunoassay was developed to detect serum complement-fixing antibodies in virus diseases. This assay utilized conglutinin-covered plastic beads as the solid phase to detect specific antibody-antigen complexes that competed for complement with a probe complex comprised of Escherichia coli beta-galactosidase and its specific antibody. Binding to the solid phase is C3bi mediated, and when specific antibody-antigen complexes are not present the probe is bound and an enzymatic reaction ensues. This type of competitive assay was introduced in the field of immunopathology for investigating circulating immune complexes by Manca et al. (Clin. Immunol. Immunopathol. 16:131-141, 1980). The assay gave satisfactory results in terms of specificity, reproducibility, and handling, enabling laboratories to obtain results in 5 h. The sensitivity of the method coincided with that of the complement fixation test. However, this technique offers several advantages over conventional complement fixation because it requires less time, is easier to perform, and gives more reliable quantitative results. The data obtained indicated that this competition assay offers a feasible alternative to conventional complement fixation tests and should be useful in routine diagnostic applications and in seroepidemiological surveys.
Comparison of the Staph-Ident System with a Conventional Method for Species Identification of Urine and Blood Isolates of Coagulase-Negative Staphylococci
Authors: Aldridge Kenneth E. , Stratton Charles W. , Patterson Lyndell S. , Evans Martin E. , Hodges Rondy L.
Published: January 2020

The Staph-Ident system (Analytab Products) for species identification of coagulase-negative staphylococci was compared with the conventional method of Kloos and Schleifer (21). A total of 101 clinical isolates from urine cultures and 95 clinical isolates from blood cultures were studied: overall agreement between the two methods was 86%. We concluded that the Staph-Ident system is a practical test for most clinical microbiology laboratories and that results obtained from this rapid test are comparable to those obtained from the more cumbersome conventional method. Additional investigations are needed to determine the clinical relevance of such species identification.
Enterotoxigenic and enteroinvasive Escherichia coli strains belonging to a new O group, O167
Authors: Gross R J , Thomas L V , Cheasty T , Day N P , Rowe B , Toledo M R , Trabulsi L R
Published: January 2020

A new Escherichia coli O group, O167, is described. Its O antigen is related to that of Shigella boydii 3. A total of 29 strains belonging to the new O group were examined. Three strains were determined to be invasive by the Sereny test and by tissue culture tests and were non-enterotoxigenic. All three were nonmotile and failed to decarboxylate lysine. A total of 26 strains were noninvasive. Of these, 25 were motile, 24 decarboxylated lysine, and 19 were enterotoxigenic, 17 producing heat-stable enterotoxin only and 2 producing heat-labile enterotoxin only. This is the first description of the occurrence of enterotoxigenic and enteroinvasive strains in the same E. coli O group.
Simplified method for typing herpes simplex virus by restriction endonuclease analysis
Authors: Arens M Q , Swierkosz E M
Published: January 2020

We have developed a simplified method for unambiguously typing herpes simplex virus. The method depends on the production of cell-associated virus at 34 degrees C and subsequently, on the separation of cellular DNA and viral DNA by Dounce homogenization and the removal of nuclei by centrifugation. Viral nucleic acid was prepared from the cytoplasmic fraction and analyzed after restriction endonuclease cleavage. The method obviates the use of radioactive isotopes, and the viral DNA is effectively free of interfering cellular DNA.
Simple Method for Demonstration of Differential Colony Morphology of Plasmid-Associated Virulent Clones of
Yersinia enterocolitica
Authors: Mazigh Daniel , Alonso Jean Michel , Mollaret Henri H.
Published: January 2020

Virulent (plasmid-associated) strains of
Yersinia enterocolitica
grown on RPMI 1640 agar (RPMI-1640 medium [Flow Laboratories] with 40 mM HEPES and 1.5% [wt/vol] purified agar [Difco]) dissociated into small and large colonies. The autoagglutination test (a marker of virulence) is regularly positive with small colonies and negative with large colonies. Avirulent
Y. enterocolitica
strains gave only large colonies on RPMI 1640 agar.
Rapid, economical diagnosis of enteric fever by a blood clot culture coagglutination procedure
Authors: Mikhail I A , Sanborn W R , Sippel J E
Published: January 2020

Coagglutination tests with Salmonella A, D, Vi, and polyvalent antiserum-sensitized staphylococcal cells were compared with conventional culture methods for detecting salmonellae in ox bile cultures of blood clots from enteric fever patients. The coagglutination tests appeared equally as effective as conventional subculture methods for detecting positive cultures (95% agreement). In addition, the coagglutination method yielded earlier results at reduced cost.
Evaluation of the Sensititre system for identification of Enterobacteriaceae
Authors: Staneck J L , Vincelette J , Lamothe F , Polk E A
Published: January 2020

The Sensititre identification system (Seward Laboratory/GIBCO Laboratories) consists of a microplate containing a pattern of 24 biochemicals repeated four times together with an automatic inoculation device and a microcomputer-assisted data interpretation component. A total of 1,415 isolates of Enterobacteriaceae plus 6 isolates of other glucose-fermenting gram-negative bacilli were tested in three hospital laboratories in parallel with API 20E (Analytab Products). Discrepancies were resolved by conventional biochemical testing. Sensititre yielded correct identifications at the species level with 94.6% of the isolates and at the genus level with an additional 1.9%. API 20E yielded correct species identification with 91.1% and genus only identification with an additional 6.7% of the isolates. For the routine identification of clinical Enterobacteriaceae isolates, the Sensititre system compares favorably with API 20E and offers clinical laboratories the economy of a microtiter plate system as well as the benefit of a microcomputer capable of other microbiological and data management applications.
Fluorescence immunoassay and passive latex agglutination as alternatives to hemagglutination inhibition for determining rubella immune status
Authors: Fayram S L , Nakasone A , Aarnaes S , Zartarian M , Peterson E M , de la Maza L M
Published: January 2020

Three different assays for detection of rubella antibodies, hemagglutination inhibition (HAI), fluorescence immunoassay (FIA), and passive latex agglutination (PLA) were used to test 297 human serum samples. Overall agreements for immune status were as follows: HAI versus FIA, 95.3% (283 of 297); HAI versus PLA (1:10 dilution), 96.3% (286 of 297); HAI versus PLA (undiluted), 93.9% (279 of 297); PLA (1:10 dilution) versus FIA, 94.9% (282 of 297); and PLA (undiluted) versus FIA, 97.9% (291 of 297). The HAI test is the most time consuming, subjective, and technically difficult to perform. The FIA and PLA tests are very rapid and less labor intensive. In addition, the FIA offers an objective determination of the patient's rubella antibody level.
Association of
Streptococcus bovis
Bacteremia with Bowel Disease
Authors: Reynolds Judith G. , Silva Ellen , McCormack William M.
Published: January 2020

We reviewed the medical records of 19 patients who had
Streptococcus bovis
bacteremia. Eight patients had diverticulosis, four had benign adenomatous colonic polyps, and three had adenocarcinomas of the gastrointestinal tract. Laboratory workers and clinicians should be aware of the association of
S. bovis
bacteremia and gastrointestinal disease.
An Acid Extract as a Common Antigen in
Campylobacter coli
and
Campylobacter jejuni
Strains
Authors: Rautelin Hilpi , Kosunen Timo U.
Published: January 2020

An acid extract prepared from a single strain of
Campylobacter jejuni
reacted with rabbit antisera against 21 strains of
C. jejuni
and
Campylobacter coli.
The immunogen is resistant to Formalin and to exposure to 100°C for 30 min. The antigenic extract may have practical applications in human serology.
Morphological, biochemical, antigenic, and cytochemical relationships among Haemophilus somnus, Haemophilus agni, Haemophilus haemoglobinophilus, Histophilus ovis, and Actinobacillus seminis
Authors: Stephens L R , Humphrey J D , Little P B , Barnum D A
Published: January 2020

Morphology, biochemical reactions, pigmentation, antigens, and cell envelope proteins were examined in 12 strains of Haemophilus somnus, Haemophilus agni, Histophilus ovis, and Actinobacillus seminis. All of the strains except A. seminis are related and are considered as a single Haemophilus-Histophilus (HH) group. In immunodiffusion tests, HH group bacteria had at least two antigens common to all members of the group, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that they have similar cell envelope protein profiles. A quantitatively variable yellow pigment with absorption maxima of 430 to 435 nm was present in strains of H. somnus and H. agni. The HH group did not produce catalase and grew only in air containing 10% CO2. Of 10 HH group bacteria, 9 required thiamine monophosphate for growth. A. seminis was distinguished from the HH group by its lack of yellow pigment, production of catalase, growth in air, lack of a thiamine monophosphate requirement, and different cell envelope protein profile. In gel immunodiffusion tests, A. seminis antigens produced two lines of partial identity with the HH group when antiserum against H. somnus was used. Reference strains of Haemophilus influenzae, Actinobacillus lignieresii, and Haemophilus haemoglobinophilus were compared with the test strains. In immunodiffusion tests, a single antigen was found to be common to H. haemoglobinophilus, A. seminis, and the HH group. No similarities between any of the test strains and H. influenzae or A. lignieresii were noted. The close relationship of H. somnus, H. agni, and Histophilus ovis suggests that these unofficially named bacteria may belong to a single taxon.
Detection of soluble antigens of Toxoplasma gondii by a four-layer modification of an enzyme immunoassay
Authors: Turunen H J
Published: January 2020

A sensitive four-layer modification of an enzyme immunoassay for the detection of soluble antigens of Toxoplasma gondii is described. Microtiter plates were sensitized with rabbit anti-toxoplasma immunoglobulins (6 micrograms/ml) used as the primary antibodies; guinea pig anti-toxoplasma immunoglobulins (6 micrograms/ml) were used as the secondary trapping antibodies. Horseradish peroxidase-conjugated anti-guinea pig immunoglobulins were used as the indicator antibodies. The specificity of the antigen assay was confirmed by using guinea pig immunoglobulins from preimmunization sera. The sensitivity of the antigen assay was found to be at least 10 ng of antigen protein per ml. The suitability of the method for detecting antigens of T. gondii in different specimens was studied by experimental toxoplasma infection in mice. Antigenic components of T. gondii could be detected in different tissue specimens from infected animals from the first day after infection onwards. Toxoplasma antigen in serum and urine samples from infected mice reached detectable levels on day 2 after infection followed by a linear increase in antigen concentration in succeeding samples. This method might offer a valuable aid for a rapid etiological diagnosis also in human cases of acute toxoplasmosis.
Killer system: a simple method for differentiating Candida albicans strains
Authors: Polonelli L , Archibusacci C , Sestito M , Morace G
Published: January 2020

The killer effect of 37 species of Candida, Cryptococcus, Hansenula, Pichia, Rhodotorula, Saccharomyces, and Trichosporon on 100 Candida albicans isolates of human and animal origin was studied. All of the C. albicans cultures were sensitive to one or more killer yeasts. The factors affecting the killer phenomenon on C. albicans were investigated for realizing a simple system for the differentiation of the 100 C. albicans isolates. By using this system, it was possible to differentiate up to 512 isolates of C. albicans according to their susceptibility to the killer effect of nine selected killer yeasts. The use of this method as an epidemiological marker in the case of presumptive nosocomial infections due to C. albicans is also reported.
Determination of antigenic specificity and relationship among Haemophilus pleuropneumoniae serotypes by an indirect hemagglutination test
Authors: Mittal K R , Higgins R , Lariviere S
Published: January 2020

Serological properties of antigens extracted from strains of Haemophilus pleuropneumoniae belonging to seven different serotypes were investigated. Antisera were prepared in rabbits against Formalin-treated whole cell suspensions as well as autoclaved cell suspensions. Saline and heat extracts and their alcohol precipitate antigens of H. pleuropneumoniae were used in the indirect hemagglutination test. All the antigens used were easily adsorbed directly onto sheep erythrocytes. Saline extract antigen showed maximum type specificity. Heating of the whole cell suspension revealed the cross-reactive minor antigenic determinants. Thus, the heat extract preparations had both type-specific and species-specific antigens. It is suggested that the indirect hemagglutination test may be useful for both serotyping and serodiagnosis of H. pleuropneumoniae infections in pigs.
Relative substrate affinity index values: a method for identification of beta-lactamase enzymes and prediction of successful beta-lactam therapy
Authors: James R
Published: January 2020

Using a nitrocefin competition assay, I determined the relative substrate affinity index (RSAI) values of nine clinically significant beta-lactamase enzymes against a range of beta-lactams. Using selected beta-lactam substrates, I observed large differences in the RSAI values of the nine enzymes that were sufficient in many cases to positively identify specific enzymes. I made use of the unique RSAI values of SHV-1, TEM-1, and TEM-2 beta lactamases with cefoxitin to screen for the presence of these enzymes in Klebsiella aerogenes clinical isolates. The RSAI values also allow for the prediction of the outcome of beta-lactam therapy against specific beta-lactamase-producing isolates.
Evaluation of slide agglutination methods for identifying group D streptococci
Authors: Chang G T , Ellner P D
Published: January 2020

Three commercial reagents for the rapid identification of group D streptococci by slide agglutination were evaluated. These included SeroSTAT (Scott Laboratories, Fiskeville, R.I.), Streptex (Wellcome Laboratories, Research Triangle Park, N.C.), and Phadebact (Pharmacia Diagnostics, Piscataway, N.J.). The methods included direct colony testing, enzyme extraction with pronase, and broth culture. A total of 72 strains of group D streptococci were tested. The SeroSTAT and Streptex reagents with pronase extraction each identified 65 (90%) of the strains. The SeroSTAT reagent was somewhat more specific since it did not cross-react with other streptococci of the viridans group. The Phadebact reagent was nonreactive. We conclude that the latex reagents can be very useful for the quick recognition of group D streptococci in the clinical laboratory.
Radioimmunofocus assay for quantitation of hepatitis A virus in cell cultures
Authors: Lemon S M , Binn L N , Marchwicki R H
Published: January 2020

A new method is described for the quantitation of hepatitis A virus in cell cultures, based on the immune autoradiographic detection of foci of infected cells (radioimmunofoci) developing beneath an agarose overlay 14 days after the inoculation of petri dish cultures of continuous African green monkey kidney cells (BS-C-1). The number of foci developing in each culture was linearly related to the dose of hepatitis A virus (either HM-175 or PA-21 strain) inoculated. Focus development was prevented by prior incubation of virus with specific antisera, and the specificity of the radiolabeled antibody reaction was confirmed in competitive blocking experiments. This new assay method retains many of the advantages of conventional plaque assays for virus. Compared with existing end-dilution methods for the quantitation of hepatitis A virus, the radioimmunofocus assay offers greatly improved accuracy and comparable sensitivity, yet is relatively rapid and highly conservative of reagents.
Naturally occurring antibodies in human sera that react with Haemophilus influenzae type b ribosomal vaccine
Authors: Lynn M , Katz M A , Santucci T F
Published: January 2020

Sera from populations of normal adults and children as well as sera from children with systemic Haemophilus influenzae type b disease were tested for antibodies reacting with ribosomes from H. influenzae type b. Adults generally had high titers of antibody, with 90% having titers greater than 1:64. The distribution of titers approximated a normal curve. Among normal children, there was more variability between individual titers, with the median titers ranging between 1:64 and 1:128. In contrast, acute-phase sera from children with systemic H. influenzae type b disease all had titers of 1:16 or less. Two convalescent-phase sera had high titers. Absorption experiments ruled out cross-reaction between ribosomes and type b capsular material. Ribosomes from two unrelated type b strains were completely cross-reactive, whereas absorption with ribosomes from a type c strain led to significantly decreased titers in three of four sera. Absorption of sera with ribosomes from Pseudomonas aeruginosa and Streptococcus pneumoniae also decreased titers, indicating that these antibodies may have been induced by ribosomes of other bacteria.
Microtiter determination of measles hemagglutination inhibition antibody with filter papers
Authors: Nakano J H , Miller D L , Foster S O , Brink E W
Published: January 2020

Epidemiological studies of measles and measles immunization frequently require determination of measles antibody status. In developing countries, where venipuncture is frequently unacceptable and where refrigerated storage of serum specimens is often unavailable, microtiter techniques not requiring refrigeration are required. We developed a filter paper technique that measures measles hemagglutination inhibition antibody and meets these criteria. Comparison of separately collected venous blood and peripheral blood collected on filter paper demonstrated 97% agreement in terms of presence or absence of antibody. In 30 of 32 measles specimens, 94% of titers were the same or varied by less than 2 twofold dilutions.