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Biomedical subjects

E A Edwards

Publications and source records attributed to E A Edwards.

At least 55 records · Page 3Linked to original sources
PubMed1980

Quality control in tuberculosis bacteriology. 2. The origin of isolated positive cultures from the sputum of patients in four studies of short course chemotherapy in Africa.

During intensive bacteriological follow-up of 2123 patients who had received short course chemotherapy regimens in 4 controlled clinical trials in Africa and had not had a bacteriological relapse, 405 isolated positive cultures were obtained from 37 429 sputum specimens in 3 East African laboratories. These cultures might have arisen as a result of clerical error, of transfer of bacilli from positive to negative specimens in the laboratory or from the lesions of the patients. Clerical error in the labelling of specimens or the recording of results did not seem a frequent cause, since isolated positive cultures contained many fewer colonies than cultures from other positive specimens being processed at the same time. Several of evidence suggested that some isolated positive cultures arose from the lesions of patients: a decrease in their incidence occurred in successive time periods after chemotherapy; the number of isolated positives per patient departed significantly from the Poisson distribution; they were more often drug resistant than other cultures processed at the time; positive cultures were obtained less frequently from known autoclaved specimens inserted among the the study specimens than from the study specimens themselves; no association was found between the incidence of isolated positive and of specimens containing numerous viable M. tuberculosis being processed at the same time. Nevertheless some of these cultures probably arose by transfer in the laboratory, since the rates at which transfer were known to occur differed in the 3 laboratories and corresponded to the rates of obtaining isolated positive cultures.

Africa, Eastern↗
PubMed1980

Coagglutination and counterimmunoelectrophoresis for detection of pneumococcal antigens in the sputum of pneumonia patients.

Coagglutination was compared with counterimmunoelectrophoresis (CIE) for sensitivity and specificity in the detection of pneumococcal antigens in sputum. Initial sputum samples from patients with pneumococcal pneumonia (less than 12 h of antibiotic therapy) were positive for antigens in 37 of 44 cases (84%) by either test. There was a decline in the number of positive results with sputum samples obtained during continuing antibiotic therapy, but the decline was greater with CIE (only 29% of samples were positive at 3 days of therapy) than with coagglutination (61% of samples were positive at 3 days of therapy) (P less than 0.05). Sputum from 3 of 11 patients (27%) and from 2 of 11 patients (18%) with nonpneumococcal pneumonia was positive for pneumococcal antigens by CIE and coagglutination, respectively, indicating a similar degree of non-specificity. Coagglutination produced the same results as CIE with sputum from patients with chronic bronchitis but without pneumonia; 9 of 23 of these patients were positive. Coagglutination was simpler to perform than CIE and required only a fraction (about 1/30) of the antiserum required for CIE. These advantages, plus the greater sensitivity of coagglutination with sputum samples obtained during antibiotic therapy, suggest that coagglutination is preferable to CIE.

Agglutination Tests↗
PubMed1980

Enrichment culture coagglutination test for rapid, low-cost diagnosis of salmonellosis.

Specific diagnosis of salmonellosis by conventional culture and identification methods usually requires 2 to 4 days. Since Salmonella may be disseminated from infected individuals during this period, this amount of time required for diagnosis may be too slow to aid in epidemic control. To obtain earlier diagnoses of salmonellosis, a coagglutination test was used for rapid, simplified detection of Salmonella oranienburg antigens in enrichment broth cultures of fecal specimens from infants involved in a nursery outbreak. Two selective enrichment broths were used, selenite cystine and dulcitol selenite. These were compared in parallel for efficiency by subculture on deoxycholate lactose sucrose, MacConkey, xylose lysine deoxycholate, and tryptic soy lactose teepol agars. These overnight enrichment broth cultures of stool specimens were also examined by a coagglutination slide test with stabilized protein A-containing staphylococci sensitized with antisera for Salmonella antigens C1, E, and Vi. Of 113 diarrhea stool specimens tested, 86 were positive by conventional culture, 82 were positive by dulcitol selenite-coagglutination, and 55 were positive by selenite cystine-coagglutination. All these tests were negative on 50 stool specimens from infants in a noninfected nursery. Salmonellae were specifically detected in stool cultures within 20 h by the coagglutination technique. This early detection of Salmonella antigens provided a useful adjunct to culture for rapid diagnosis of salmonellosis.

Agglutination Tests↗
PubMed1978

A second study of the use of community leaders in case-finding for pulmonary tuberculosis in Kenya.

This is the second study of case-finding activities for tuberculosis suspects undertaken in 2 locations of Machakos District. Three methods were investigated, namely (1) the requestioning of the Community Elders 1 year or more after a first questioning in the original study, (2) the examination of patients registered in the District Tuberculosis Register from 1969--1974 and (3) the examination of their close contacts. Requestioning the Elders produced a total of 421 suspects, 129 (31%) of whom had not been identified a year previously. The yield of freshly identified smear-positive, culture-positive cases was 0.7 per 100 suspects examined and of all culture-positive cases was 1.7. However, all the smear-positive and 1.0 per 100 of the culture-positive cases were old patients who had previously been registered in the District Tuberculosis Register. Of the 181 patients with tuberculosis in the Register bacteriological results were available for 97; of these 6 were smear-positive, 9 culture-positive--yields of 6.2 smear-positive, culture-positive cases per 100 registered persons examined. The corresponding yields for the 63 persons who had been registered as having pulmonary disease were 9.5 and 14.3. Of the 9 culture-positive, 7 had strains resistant to isoniazid, but all were sensitive to streptomycin. The examination of the 628 close contacts of the registered patients produced only 3 culture-positive cases, none of whom was smear-positive--a yield of 0.5 culture-positive cases per 100 contacts examined. All 3 strains were sensitive to isoniazid and streptomycin.

Communicable Disease Control↗
PubMed1977

Differences between sexes in the nasopharyngeal carriage of Neisseria meningitidis.

Nasopharyngeal carriage of Neisseria meningitidis was investigated among male and female students sharing similar occupational and living environments at the U.S. Naval Hospital Corps School, Great Lakes, Illinois, in 1972-1973. When students beginning the study without meningococcal carriage were evaluated, meningococcal acquisition, weekly carrier prevalence, number of different serogroups carried, proportion of serogroup Y carriers, and average duration of group Y carriage were approximately equal for each sex. In this comparable group of men and women, there was no evidence of differences in meningococcal carriage associated solely with the sex of the host.

Carrier State↗
PubMed1977

Immunological investigations of meningococcal disease. III. Brevity of group C acquisition prior to disease occurrence.

A surveillance program to determine group C meningococcal acquisition in military personnel during an epidemic was made. Data from fortnightly nasopharyngeal cultures show that individuals who were admitted with meningococcal disease acquired the organism within a week of disease onset. There were 24 company/platoons in which a single case occurred. Six company/platoons had 2 cases each. While other conditions which could act as predisposing factors were not ruled out, the data here favor acute respiratory disease as a predisposing factor(s) that may cause the increased incidence of meningococcal disease seen in military recruits. The exact mechanism is yet to be defined.

Antibodies, Bacterial↗
PubMed1976

A longitudinal study of Mycoplasma pneumoniae: infections in Navy recruits by isolation and seroepidemiology.

A longitudinal serologic study of M. pneumoniae infections in two recruit training centers with grossly different climates showed that the frequency of this infection peaks in the late summer-early fall and to a lesser degree in the spring at both training centers. Seroconversions (four-fold or greater increase in titer) were as high as 45-57% in some recruit companies during the late summer peak. M. pneumoniae isolations from men admitted to the dispensary or hospital with pneumonia during the major peak season were as high as 32%. While M. pneumoniae infections are not generally life-threatening, the high incidence of infections observed in personnel during recruit training is of major concern and warrants consideration of effective control measures.

Florida↗
PubMed1976

Method for identifying Salmonella and Shigella directly from the primary isolation plate by coagglutination of protein A-containing staphylococci sensitized with specific antibody.

A technique is described that allows presumptive identification of either Salmonella or Shigella organisms directly upon the original isolation plate, in this case, MacConkey agar. This was accomplished by applying a drop of specifically sensitized protein A-containing Staphylococcus aureus over a "suspected" colony or several colonies of organisms grown on MacConkey agar. The plate is tilted to and fro to allow mixing of the particles with specific antigen that ir readily solubilized from the colony and observing for agglutination of the sensitized particles by use of a dissecting microscope. The agglutination can frequently be seen within 15 s, increasing in intensity over a 2-min period. The polyvalent Salmonella antiserum was slower in developing strong agglutination (1.5 to 2 min) compared to particles sensitized with group-specific antisera (15 to 45 s). A high-titer antiserum was important for a test reagent to have the required sensitivity.

Agar↗
PubMed1976

Identification of group a streptococci by reverse passive hemagglutination.

A method for preparing sensitized human O erythrocytes with specific antibody is reported. Whole sera or 40% ammonium sulfate insoluble globulin fractions did not satisfactorily sensitize erythrocytes to agglutinate in the presence of either group specific polysaccharide of group A beta-hemolytic strepticocci or antigen produced during colony formation. Antibody purified by affinity chromatography sensitized the erythrocytes to rapidly agglutinate in the presence of either antigen. No spontaneous or "pseudo-immune" agglutination occured when the sensitized erythrocytes were suspended in human serum. Such sensitized human cells, while more difficult to prepare than sensitized staphylococci, should be suitable for detecting bacterial or viral antigens in vivo.

ABO Blood-Group System↗
PubMed1975

Visualization by immune electron microscopy of viruses associated with acute respiratory disease.

A sensitive and rapid method for detecting adenovirus and influenza viruses has been demonstrated by using both the direct and indirect immune electron microscopy technique. The indirect method was from 4 to over 32 times more sensitive than the direct method. The technique appears to have the sensitivity approaching tissue culture methods, but is much more rapid, requires less laboratory support personnel and space, and should lend itself to detection of noncytologic agents. These data suggest a new role for the electron microscope in diagnostic virology.

Adenoviridae↗