Showing papers on "Typing published in 1980"

The development of a phage-typing system for group-b streptococci

Abstract: A typing system for group-B streptococci, based on the use of 24 phages, has been evaluated. Used in conjunction with serotyping, it gave highly discriminating and reproducible results.

The epidemiological type identification of Serratia marcescens from outbreaks of infection in hospitals

Abstract: SUMMARY A study of serological, bacteriocine and phage typing of Serratia marcescens was made. Specific O-antisera of adequate titre were relatively simple to prepare but H-antisera exhibited many heterologous agglutination reactions amongst the type strains. Most of these cross-reactions were not reproduced when immobilization tests with H-sera were performed. Direct haemagglutination tests were used to establish the presence of fimbriae amongst the H-type strains and the results of agglutination tests with non-fimbriate variants of strains indicated that fimbrial antibody in high titre was present in some sera. Replicate typing of 100 pairs of cultures by the phage-typing method indicated that small variations in pattern were common and that larger variations occurred occasionally. Therefore diSerences in pattern of less than two strong reactions should not be taken as evidence that strains can be distinguished. Cultures of S. marcescens, 273 in total, from six outbreaks of infection in British and European hospitals were typed by O-serology, H agglutination and immobiliza.tion tests, phage typing and bacteriocine susceptibility by a cross-streaking method. The typability of strains by each method was high but the results suggested tha.t no single method was sufficiently discriminating to be used alone for typing. Comparison of the H-type and typing patterns of members of the same O serogroup from incidents of infection showed that reliable results were obtained by H-typing or by phage and bacteriocine typing after the application of the appropriate ' diSerence ' rule. The greatest discrimination between strains of the same O-group was obtained

Rapid typing of herpes simplex virus isolates by deoxyribonucleic acid:deoxyribonucleic acid hybridization.

Abstract: A method for typing clinical isolates of herpes simplex virus was developed. It utilizes hybridization between unlabeled deoxyribonucleic acid from infected cultures and tritium-labeled virus deoxyribonucleic acid, and it can be completed within a day using a single roller-tube culture of the clinical isolated. The data obtained are inherently quantitative, and the method yields unequivocal identification and typing. Thirty-nine coded clinical isolates were all correctly typed by this method.

Computer analysis of Staphylococcus aureus phage typing data from 1957 to 1975, citing epidemiological trends and natural evolution within the phage typing system.

Abstract: Computer analysis of Staphylococcus aureus phage ty ping data collected for over 18 years in a large research hospital showed a drastic decrease in the number of hospital epidemic strains. Phage lysis patterns gradually modified from those of earlier years and were a reflection of changes within the S. aureus reservoir, and not within the typing phages, since the typing phages were used from stable lyophilized stocks. There was increasing cross-lysis of S. aureus strains by phages of lytic groups I, II, and III, such that this grouping was no longer epidemiologically valid. A 61% increase in unique strains occurred from the period 1957 to 1975. Disappearance of the widely recognized epidemic strains was followed by a proliferation of unique strains with individual phage patterns. These increased from 38% in the period 1957 to 1962 to 62% in the period 1969 to 1975, indicating a trend toward a "one patient-one strain" situation. Nontypable strains decreased in more recent years from 16% (1957 to 1975) to 7% in 1978, following introduction of phages 94, 96, 292, and D-11. Pandemic S. aureus strain 80/81 first appeared in this hospital in 1959, 5 years after it was first reported in the United States. Strain 80/81 disappeared from the hospital in 1963, partly due to the advent of methicillin.

Discrimination of urinary strains of Escherichia coli by five typing methods.

Abstract: Serotyping is probably the most widely used method for typing strains of Escherichia coli, but the range of antisera required restricts its use to a few specialised laboratories. Other typing methods are available, and the purposes of this investigation were to evaluate the techniques of biotyping (Crichton and Old, 1979), resistotyping (Elek and Higney, 1970) and haemagglutinin typing (Duguid, Anderson and Campbell, 1966; Duguid, Clegg and Wilson, 1979), to assess their convenience for use in routine diagnostic laboratories, and to determine whether combinations of these methods would lead to more precise identification of sequential isolates of E. coli from patients with urinary-tract infections.

Self-Assessments of Five Types of Typing Ability.

Abstract: The potential usefulness of self-assessments of typing ability were examined from a personnel selection perspective. A sample of 156 “business ready”, Phoenix area high school students estimated their abilities to type each of the following types of materials in units of net words per minute: 1. straight copy 2. letters 3. revised manuscript 4. numbers 5. tables. The students then took the analogous portions of the Typing Test for Business, Self-assessment of straight copy typing ability emerged as the best predictor of tested typing ability of all types. Because of the substantial number of minority students in the sample (N= 69, 44.2%), differential prediction was studied. Self-assessments of revised manuscript, numbers, and tables typing abilities were significantly higher for the majority group than for the minority group. Typing test performance was significantly higher for the majority group across straight copy, letters, revised manuscript, and tables subtests. Minority group members were generally less accurate in self-assessment of their typing ability. Subgroup regression lines were compared by means of Potthoff's analysis, and subgroup differences in prediction of tested typing ability from self-assessments of typing ability were found.

An analysis of the standard English keyboard

Abstract: A study of the nature of hand and finger motions in typing process was made, based on the data on time intervals between key strokes. Many of the results obtained confirm those formerly obtained by Dvorak and other researchers. In addition, it was [bund that each key sequence is affected by its context, thus proving that the mental aspects of typing directly affects its productivity, and that the performance analysis on a particular keyboard arrangement is not sufficient to predict the performance on other arrangements. Based on these results, the current English keyboard is judged to be a less than ideal tool for typing. However, when carefully examined, even a rudimentary measurement of certain factors of typing behavior would lead to a good understanding of some pertinent aspects of the typing process. We faced the problem of keyboard optimization in the process of developing a Japanese-input keyboard. Our approach here is based on the measurement of the time interval of key strokes, obtained from the typing performance of English text by a proficient typist, In this paper, we first present the findings based on these data, discuss an important human factors problem involved in them, then attempt to present an evaluation of the QWERTY keyboard in this perspective.

Complexity of the HLA-D region studied by primed-lymphocyte test.

Abstract: The results obtained by mixed lymphocyte culture (MLC), HLA-D and -DR typing, and primed lymphocyte test (PLT) in the F. family give some indication of the complexity of the HLA-D region in man. Two siblings identical for HLA-A, -B, -C, -D, and -DR by typing are mutually MLC-stimulatory. PLT studies indicate that one of these siblings expresses D-region determinants of both of the mother's haplo-types, suggesting an intra-D recombinant. These results suggest that the D region contains genes for a number of different determinants.

Single bacteriocin typing scheme for the Vibrio group of organisms.

Abstract: A total of 743 strains of O-I "agglutinable" and 293 strains of O I "inagglutinable" Vibrio cholerae were subjected to bacteriocin typing based on deferred antagonism of eight indicator bacteria, including two strains of V. cholerae, by the method of Chakrabarty et al. (Infect. Immun. 1:293-299, 1970). A minor modification that was effected in the typing medium was replacement of iodoacetic acid by ammonium chloride (at a final concentration of 0.003%) which appeared to regulate bacteriocin production more accurately and increase the stability of the types. Of the agglutinable strains, 94% were found to be bacteriocinogenic and could be fitted into 11 of the earlier-reported types (Chakrabarty et al., Infect. Immun. 1:293-299, 1970), and 6 newer types were recognized. Likewise, 285 (90.7%) of the inagglutinable strains were found to be bacteriocinogenic and could be accommodated within 10 original and 8 newer types identified for the inagglutinable vibrios. Thirteen types were common to the two groups of vibrios. The single bacteriocin typing scheme appeared to be simple and adequate for both groups of organisms, and the producer as well as the indicator bacteria behaved remarkably stably in this typing scheme over many years.

A simple method for typing clinical isolates of herpesvirus simplex: replication in the presence of 2h-1,3-oxazine-2,6 (3h)-dione (oxauracil)

Abstract: A rapid simple method for the typing of wild HSV isolates based on selective inhibition of HSV-2 replication by the pyrimidine analogue oxauracil (2H-1,3-oxazine-2,6(3H)-dione) has been developed. Chi-square analysis of the results of typing of 30 wild strains by serum neutralization tests, immunofluorescence, and oxauracil-inhibition indicates no significant differences in assignment of types to the isolates. The oxauracil-inhibition test obviates confusion of typing resulting from use of immune sera containing cross-reactive antibodies. We conclude oxauracil typing is a simple, rapid, and precise test which can be performed in any laboratory capable of isolating HSV.

Typing Mycobacterium tuberculosis with mycobacteriophage Bo4.

Abstract: Summary Mycobacteriophage B04 grown on the indicator host strain Mycobacterium fortuitum SN203 was restricted and modified by Mycobacterium tuberculosis H37Rv. Phage B04·H37Rv was restricted and modified by the alternate host SN 203. M. tuberculosis strain Myc 1025 was described as a r-m- isolate. By using the mycobacterial prototype strains for phage typing wild M. tuberculosis isolates, it was demonstrated that only the modified phage B04·H37Rv was a potential typing phage.

Active perfringocin typing of food poisoning strains of Clostridium perfringens type A--a new tool for epidemiological investigations.

Abstract: Active perfringocin typing, as an epidemiological tool, for investigation into food poisoning outbreaks due to C. perfringens type A has been developed. Ninety strains included in this study were from England, America, India, Japan, France and Canada Nine indicator strains exhibiting different patterns of inhibition were selected for perfringocin typing. With these indicator strains, 81.11 per cent of the strains were typable into ten perfringocin types. Type "a" and "b" alone could type 47.92 per cent of the strains. Type "f" was predominantly found to be for the American strains and "b" and "c" for the Indian strains. Active perfringocin typing developed for the first time for the food poisoning strains of C. perfringens type A was expected to prove useful in the epidemiological investigations.

Sex-Role Typing: A Methodological Note

Abstract: Contemporary measures of sex-role affiliation, which emphasize the relative independence of masculine and feminine attributes, typically rely upon a median-split procedure to generate a four-fold typology, e.g., masculine, feminine, indeterminant, and androgynous types. Methodological problems created by this classification technique are illustrated for one combined male/female sample and three male samples given the PRF ANDRO. The number in each standardization sample was Combined, 772; Males, 386; Alcoholics, 123; Veterans of Foreign Wars, 73. Sex-role typing was markedly influenced by the sample from which median cutting scores were derived.

Hemagglutination Typing ofEscherichia coli: Definition of SevenHemagglutination Types

Abstract: andmannose-resistant hemagglutinins produced byEscherichia coli isolated fromhumansources. HA typing isperformed bytesting CFAagar-grown E.coli cells forHA withhuman,bovine, adult chicken, African Greenmonkey, andguinea pigerythrocytes inthepresence and absence ofmannose. SevenmajorHA types, designated HA typeIthrough HA typeVII, havebeendefined according totheHA patterns produced by1,334 test cultures consisting of33colonization factor antigen I(CFA/I)-positive enterotoxigenic E.coli (ETEC), 37CFA/II-positive ETEC,614isolates belonging tothe classical enteropathogenic E.coli, orEPEC,serogroups, 446non-ETEC, nonEPECstool isolates, and204bacteremia-associated E.coli. Facultatively enteropathogenic E.coli (FEEC) serogroups, which arethecausative agents ofextraintestinal infections butalso sporadic cases ofenteritis, comprised 38%ofthestool isolates and91%oftheblood isolates examined. Previous observations concerning theHA patterns ofCFA-positive ETEC andtheEPEC wereconfirmed. A significant correlation wasfound between FEECserogroups andtheproduction ofmannose-resistant HAwithhuman, monkey, andusually chicken erythrocytes (the HA patterns designated HA typeVI). Alarge majority (80.2%) oftheFEEC strains belonging tothemostfrequently isolated serogroups fromcases ofbacteremia(01, 02,04,06,07,and018)produced typeVIHA patterns. Stool isolates belonging tothese sameserogroups were59.2% positive forHA typeVIpatterns. Incontrast, only17.4%ofthenon-FEECstool isolates and1.9%oftheEPEC isolates belong toHA typeVI.Oftheblood isolates, theHA typeVIphenotype wastwotimes moreprevalent amongKl-positive E.coli thanamongKl-negative E.coli, 70.6versus 31.1%. Theseresults suggest thatsurface-associated hemagglutinins ofE.coli, manyofwhich areknowntobefimbriae, should beconsidered inaddition toserotype (O:K:H antigenicity) inthedescription ofisolates. We previously described ahemagglutination (HA)typing system forEscherichia coli based upontests forHA ofhuman, bovine, chicken, andguinea pigerythrocytes inthepresence and absence ofmannose(11). Theimpetus fordevelopment ofthis HA typing system wasthat thefimbrial colonization factor antigens CFA/I andCFA/II ofenterotoxigenic E.coli(ETEC) aredetectable asmannose-resistant (MR)he