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Biomedical subjects

E Neter

Publications and source records attributed to E Neter.

At least 19 recordsLinked to original sources
PubMed1984

Recovery of Salmonella group B from blood and Salmonella group C2 from feces and serological evidence of dual infection in one patient.

A patient with a dual Salmonella infection is described. Salmonella group B was recovered from three blood culture sets but was not detected in seven stool cultures. Salmonella group C2 was isolated from three of seven stool cultures but was not recovered from blood cultures. Specific, non-cross-reactive antibodies to Salmonella groups B and C2 were detected in the sera of the patient by passive hemagglutination assays.

Adult↗
PubMed1983

The effects of prolonged retention of diaphragms on colonization by Staphylococcus aureus of the lower genital tract.

To determine whether prolonged retention of diaphragms alters Staphylococcus aureus colonization of the lower genital tract, 183 nonpregnant, asymptomatic women were screened for the presence of this pathogen in the cervix and upper vagina. Nineteen (10.4%) had positive cultures: 5 from the vagina, 8 from the cervix, and 6 from both sites. A second examination with quantitation revealed the presence of S. aureus in 7 of the 19 patients. In five of the six available patients, the number of staphylococci increased significantly after prolonged (24 hour) retention of diaphragms and decreased in one subject only. In two additional patients S. aureus was recovered after, but not before, the use of diaphragms. An increase in the number of other microorganisms also was noted after prolonged retention of diaphragms. In vitro study of the spermicide nonoxynol-9 revealed that it had no inhibitory activity on staphylococci or group B streptococci but was highly effective against Streptococcus pneumoniae.

Adolescent↗
PubMed1983

Modification of the lipid moiety of the enterobacterial common antigen by the "Pseudomonas factor".

Pseudomonas aeruginosa produces a factor (PF) which affects the enterobacterial common antigen (ECA); resulting in failure of the antigen to modify erythrocytes for hemagglutination by ECA antibodies. In the present study the nature of PF was determined. Pronase treatment abolished its activity, indicating the protein nature of PF. PF-treated ECA no longer coated erythrocytes but still reacted with ECA antibodies in immunoelectrophoresis tests with monospecific antiserum to ECA, although differences were noted between the precipitation patterns of PF-treated and untreated ECA. Therefore, PF does not significantly affect the antigenic determinant of ECA but rather affects its lipid carrier, an L-glycerophosphatide. Accordingly, differences in the sugar chain could not be detected by high-voltage paper electrophoretic examinations of partial hydrolysates of PF-treated and untreated ECA. PF liberates all fatty acids from ECA, similarly to commercial lipases, as evidenced by the liberation of unsubstituted glycerol upon HF degradation at 0 degrees C of PF-treated ECA. The lipase activity of PF is indicated also by the observation that a strain of P. aeruginosa with reduced lipase production and an exolipase-negative strain affect ECA either less or not at all. We conclude that PF is a lipase acting on the lipid moiety of ECA, which is responsible for the coating of erythrocytes, but not significantly on the serological determinant, the amino sugar chain.

Antigens, Bacterial↗
PubMed1983

Advantages of BACTEC hypertonic culture medium for detection of Haemophilus influenzae bacteremia in children.

The hypertonic and aerobic culture media in the BACTEC system were compared for the detection of Haemophilus influenzae bacteremia in children. Of 1,611 blood cultures, 30 were positive for this pathogen. The aerobic and hypertonic media gave positive results in 28 and 29 cultures, respectively. Within the first 12 h, H. influenzae was detected in the hypertonic medium in 48.5% of the positive cultures as compared to 35% for the aerobic medium. Importantly, after the first 12 h, the hypertonic medium yielded positive results sooner than did the aerobic medium, the difference being statistically significant (P less than 0.01). The hypertonic medium yielded positive results earlier than the aerobic medium in nine cultures; the reverse was seen in only one culture. Furthermore, the aerobic medium gave negative growth index readings despite growth, as shown by microscopy and subculture, in 43% of the total cultures in contrast to only 13% for the hypertonic medium, a significant difference (P less than 0.05). Thus, the present study indicates a distinct advantage of hypertonic medium compared with aerobic medium in the automated BACTEC system for earlier detection of H. influenzae bacteremia and is recommended for those age groups in which this pathogen plays a predominant role.

Child↗
PubMed1983

Production by various Pseudomonas species of a factor modifying the enterobacterial common antigen.

The enterobacterial common antigen (ECA) is a common determinant shared by almost all members of the family Enterobacteriaceae. The antigen modifies erythrocytes for agglutination by ECA antibodies. Previously it was reported that Pseudomonas aeruginosa produces a factor (PF) which destroys the erythrocyte-modifying capacity of ECA. The present investigation was undertaken to determine whether other species of this genus also produce PF. The passive bacterial hemagglutination and hemagglutination inhibition tests were used. It was observed that 47 strains belonging to 8 species of the genus Pseudomonas produce this factor and 34 strains representing 12 other species do not. Multiple strains of a given species gave concordant results. Mucoid variants of P. aeruginosa produced more of this factor than did nonmucoid isolates recovered from the identical sputum specimens from patients with cystic fibrosis. ECA treated with PF no longer modifies erythrocytes for agglutination by ECA antibodies and exerts less antibody-neutralizing capacity than untreated antigen.

Antigens, Bacterial↗
PubMed1982

Enteropathogenicity: recent developments.

Recent studies have added important new information to our understanding of the pathogenesis and ethiology of diarrheal disease. Vibrio cholerae produces a heat-labile enterotoxin, affecting cyclic AMP. A very similar heat-labile enterotoxin is produced also by certain strains of Escherichia coli, as well as by Citrobacter, Klebsiella, and Aeromonas. E. coli may also produce a heat-stable enterotoxin, stimulating guanylate cyclase activity. In order to produce the pathologic effects, E. coli first attaches to epithelial cells of the intestinal tract by means of pili or surface antigens. Enterotoxin can be demonstrated by both in vivo and in vitro tests, but none are yet suitable for routine diagnostic laboratories. A third mechanism whereby E. coli causes diarrheal disease consists of enteroinvasiveness. Campylobacter, Yersinia, and Clostridium difficile have been added to the list of enteric pathogens of man.

Animals↗
PubMed1982

Immunological activities of purified preparations of enterobacterial common antigen.

The immunological activities of three purified preparations of enterobacterial common antigen (ECA) obtained by different procedures were studied. ECA-Ma (method of A. Marx) was from Salmonella typhimurium TV149 (Ra mutant), ECA-My (method of H. Mayer) was from S. montevideo, and ECA-Ro (method of E. Romanowska) was from Shigella sonnei phase I. These preparations, on a weight basis, neutralized similar amounts of ECA antibodies, indicating that the serological activities were comparable. Neither ECA-My nor ECA-Ro elicited specific delayed-type hypersensitivity skin reactions at 24 or 48 h in immunized guinea pigs. ECA-Ma, as well as the nonpurified preparations of the antigens used for immunization, elicited reactions at 24 h but not at 48 h. Thus, ECA-specific delayed-type hypersensitivity was not detected in immunized guinea pigs. Striking differences were noted in the immunogenicity of these antigens, ECA-Ma being highly immunogenic in the rabbit in contrast to ECA-My and ECA-Ro. ECA-Ma was a potent mitogen for guinea pig spleen cells, stimulating high levels of DNA synthesis; ECA-My was only slightly active. The three antigens were mitogenic to spleen cells from both CBA/J and C3H/HeJ mice, although not to the same degree, indicating that this effect is not due to contaminating lipopolysaccharide, since the latter strain of mice is resistant to endotoxin. Since an ECA-Ma extract made from an ECA-negative mutant proved to be mitogenic to murine spleen cells, the mitogenicity is not due to the ECA haptenic determinant. The mitogenic effect is polyclonal in nature, ECA-Ma producing a maximum response on day 3. Thus, the ECA preparations are both B-cell mitogens and polyclonal activators in murine spleen cells. From these studies it is evident that the biological and immunological activities of these purified antigens depend not only on the haptenic determinant but also on associated or bound components of the preparations.

Animals↗
PubMed1982

Superiority of hypertonic culture medium for detection of Haemophilus influenzae by the BACTEC procedure.

A comparison of hypertonic (sucrose), aerobic, and anaerobic media for the detection of eight recent clinical isolates of Haemophilus influenzae type b by the BACTEC procedure revealed that the hypertonic medium, without exception, yielded diagnostic growth index values of 30 or above from 4 to 24 h earlier than did the other media. This culture medium was also superior when an increase in growth index units of 10, before a value of 30 was reached, was taken as a criterion. The number of colony-forming units increased more rapidly in the hypertonic medium as compared with the other media. These results, together with limited observations on blood cultures from patients, suggest that the sucrose medium may permit earlier detection of H. influenzae bacteremia than the aerobic medium, particularly since a growth index of 20 rather than 30 is used for the indication of bacterial growth.

Bacteriological Techniques↗
PubMed1982

The effect of Pseudomonas aeruginosa on the immunogenicity of enterobacterial common antigen.

Pseudomonas aeruginosa produces a factor (PF) which alters the enterobacterial common antigen (ECA). Its effect on the immunogenicity of two types of immunogenic ECA, namely, the ethanol-soluble preparation freed of lipopolysaccharide and the LPS-coupled form from the R-mutant E. coli 014 was investigated. The antibody response following intravenous immunization was determined by means of the hemagglutination test. It is shown that PF abolishes the immunogenicity of the former but not of the latter. PF obtained from a strain of P. maltophilia yielded the same results. Antiserum against Pseudomonas aeruginosa of types 1 and 6 neutralizes PF produced by either type. These results suggest that PF alters the lipid part and not the haptenic determinant of ECA and that this activity is neutralized by P. aeruginosa antiserum of either type 1 or type 6. This interpretation is compatible with the identification of PF as a lipase.

Animals↗
PubMed1982

Relationship between the magnitude of bacteremia in children and the clinical disease.

The relationship between the magnitude of bacteremia due to Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis and the clinical diagnosis was determined on 79 children who were not receiving prior antibiotic therapy and had fever, either in the presence or absence of focal signs of infection. Bacteremia was quantitated by the recently described Quantitative Direct Plating procedure in which heparinized blood (0.5 ml each) is plated onto blood and chocolate agar plates. Additionally, blood was cultured by means of the radiometric Bactec technique. In the case of H. influenzae and S pneumoniae, 23 (92%) of 25 patients with more than 100 organisms per milliliter of blood had meningitis or epiglottitis in contrast to only four (9.5%) of 42 patients with less than 100 organisms (P less than .001). No significant difference was noted in the magnitude of bacteremia due to N meningitidis among 12 patients with meningitis or other serious infections. The possible predictive value of the quantitation of bacteremia is illustrated by the observation of three children with seemingly mild respiratory infection and counts in excess of 100 organisms per milliliter who, within 20 hours, developed meningitis or epiglottitis. High bacterial counts of H influenzae and S pneumoniae in excess of 100 organisms per milliliter of blood should alert the physician to the existence or possible development of serious disease.

Adolescent↗
PubMed1981

Respiratory infections in infants on mechanical ventilation: the immune response as a diagnostic aid.

A prospective study was undertaken in 41 newborn infants receiving artificial respiration for evaluation of the incidence of respiratory infections. Clinical and radiologic evidence of pneumonia was compared with the appearance of serum antibodies against antigens prepared from microorganisms isolated from bronchial aspirates, and with serum and bronchial immunoglobulin M values. A significant specific immune response was documented in 24% of the patients studied. The data indicate that by correlating the clinical and radiographic findings with specific antibodies and IgM antibody responses, it is possible to document a significant number of respiratory infections. One implication of this study is that subclinical infections may not be uncommon. The significance of the presence and changes in concentration of IgM in bronchial aspirate requires further study.

Antibodies, Bacterial↗
PubMed1981

Diagnosis of bacteremia in children by quantitative direct plating and a radiometric procedure.

During a 1-year period, three bacteriological systems for detecting bacteremia in children were analyzed, namely, the BACTEC system (Johnston Laboratories, Inc., Cockeysville, Md.), the Fisher/Lederle bottle (Lederle Diagnostics, Pearl River, N.Y.), and a direct plating method of blood termed quantitative direct plating (QDP). Of 2,123 blood cultures, 135 (6.4%) were positive; Haemophilus influenzae type b, Neisseria meningitidis, and Streptococcus pneumoniae accounted for 3.4%, representing 61 patients, other pathogens accounted for 0.6%, and contaminants accounted for 2.4%. Of 72 cultures yielding H. influenzae, N. meningitidis, and S. pneumoniae, 60 were recovered by both broth systems, 2 by BACTEC only and 10 by Fisher/Lederle bottle only. The BACTEC system failed to register a positive growth index reading by 24 h in 15 cultures which were positive for H. influenzae, even though growth had occurred, as shown by positive subculture and microscopy at this time. QDP detected 89% of the cultures positive for H. influenzae and N. meningitidis, of which 55% yielded results before either broth procedure. Only 50% of the cultures positive for S. pneumoniae yielded growth on QDP. This difference in the recovery rate probably is accounted for by the number of organisms in the blood. Thus, more than 100 organisms per ml of blood were found in 71% of cultures positive for H. influenzae and N. meningitidis but in only 7% of those positive for S. pneumoniae. These studies, then, have revealed that H. influenzae, which grew well in BACTEC broth, did not, however, give a significant growth index reading during day 1 of incubation, in contrast to N. meningitidis and S. pneumoniae. The QDP system not only provided information on the magnitude of bacteremia due to H. influenzae and N. meningitidis but frequently allowed earlier diagnosis and, thus, proved to be a valuable, simple, and inexpensive supplementary technique for broth cultures, although not for the diagnosis of S. pneumoniae bacteremia.

Bacteriological Techniques↗
PubMed1981

Comparison of the quantitative direct plating method and the BACTEC procedure for rapid diagnosis of Haemophilus influenzae bacteremia in children.

The efficacy and reproducibility of the quantitative direct plating (QDP) method and the semi-automated BACTEC radiometric system (BBL Microbiology Systems, Cockeysville, Md.) were analyzed for the rapid diagnosis of Haemophilus influenzae bacteremia on the basis of 41 positive cultures from 35 patients. The QDP method detected 61% and BACTEC only 19% of the positive cultures within the first 12 h. Similarly, the QDP procedure yielded growth of H. influenzae in 56% of the cultures before a positive growth index reading was obtained with the BACTEC method. The observation that the quantitative procedure recovered H. influenzae in 88% of all positive cultures, using only 1 ml or less of blood, is attributed to the fact that 68% of the cultures had counts in excess of 100 colony-forming units per ml. The reproducibility of the QDP method was documented by the fact that duplicate blood cultures taken within a few hours of each other yielded comparable results on the number of bacteria at low (1 to 100/ml), moderate (100 to 1,000/ml), and high (greater than 1,000/ml) levels of bacteremia. We concluded that the QDP method is a valuable, simple, and inexpensive supplementary technique to the semi-automated BACTEC procedure for the rapid diagnosis of H.influenzae bacteremia in children.

Bacteriological Techniques↗