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Biomedical subjects

K M Boyer

Publications and source records attributed to K M Boyer.

At least 55 records · Page 3Linked to original sources
PubMed1983

Selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease. I. Epidemiologic rationale.

Between 1973 and 1981, 61 cases of neonatal group B streptococcal early-onset disease occurred among 32,384 infants born at Michael Reese Hospital and Medical Center, Chicago. Forty-one (67%) of the 61 affected infants were bacteremic at birth, implying intrapartum acquisition of infection. No significant deviations from the overall attack rate of 1.9 per 1,000 live births were associated with maternal demographic factors, but increased attack rates were associated with birth weights of less than or equal to 2.5 kg (7.9 per 1,000), rupture of amniotic membranes greater than 18 hr before birth (7.6 per 1,000), and intrapartum fever (6.5 per 1,000). Forty-five (74%) of the 61 affected infants and 15 (94%) of the 16 with fatal outcome had one or more of these three perinatal risk factors. Based on an intrapartum vaginal carriage rate of 16.7% among parturients with perinatal risk factors, an attack rate of 45.5 per 1,000 was estimated for infants born to colonized "high-risk" parturients, a subgroup comprising approximately 3% of our obstetric population. These findings provide a compelling epidemiologic rationale for trials of selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease.

Anti-Bacterial Agents↗
PubMed1983

Selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease. II. Predictive value of prenatal cultures.

To determine the value of prenatal cultures in defining maternal colonization status at delivery, 5,586 pregnant women were screened at prenatal visits for vaginal and rectal carriage of group B streptococci (GBS). GBS were isolated from 1,272 (22.8%). At delivery, semiquantitative cultures were obtained from 393 prenatal carriers, of whom 264 (67.2%) retained carriage at delivery. Seventeen (8.5%) of 200 women with negative prenatal cultures acquired carriage. The predictive value of a positive prenatal culture was highest (72.5%) in women with prenatal vaginal and rectal colonization and lowest (59.7%) in women with only rectal colonization. The predictive value varied inversely with the interval between prenatal sampling and delivery. In mothers with prenatal carriage, density of colonization at parturition was not predicted by the sites of prenatal colonization. Density of colonization, however, strongly influenced rates of vertical transmission to neonates and rates of heavy infant colonization. Ten infants born to prenatally cultured mothers developed group B streptococcal early-onset disease; the mothers of eight (80%) of the 10 had prenatal colonization with the homologous GBS serotype.

Ampicillin↗
PubMed1983

Selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease. III. Interruption of mother-to-infant transmission.

The effect of intrapartum ampicillin treatment on vertical transmission of group B streptococci (GBS) was examined in 575 prenatally colonized parturient women and their 580 newborn infants. Eighty women (43 receiving ampicillin) with premature labor and/or prolonged rupture of amniotic membranes were randomized. The other 495 were stratified into groups of 358 (31 receiving ampicillin) with no perinatal risk factors; 119 (28 receiving ampicillin) with premature labor and/or prolonged membrane rupture; and 23 (18 receiving ampicillin) with intrapartum fever. Ampicillin virtually eliminated vertical transmission in the treatment group with no risk factors and in both treatment groups with premature labor and/or prolonged membrane rupture. GBS colonization of neonates was detected only in women with intrapartum fever or brief (less than 1 hr) duration of treatment prior to delivery. Ampicillin treatment was associated with a highly significant reduction in maternal postpartum vaginal colonization by GBS. There were six group B streptococcal early-onset infections in infants of untreated subjects and no cases in treated subjects.

Ampicillin↗
PubMed1982

An enzyme-linked immunosorbent assay (ELISA) for human IgG antibody to the type Ia polysaccharide of group B streptococcus.

An ELISA was developed to measure human IgG antibody to the native polysaccharide antigen of GBS serotype Ia. Because the polysaccharide binds poorly to polyvinyl chloride, its adherence was enhanced by activation with cyanogen bromide and coupling to HSA in a molar ratio of polysaccharide to albumin of 1:4.5. There was minimal loss of sialic acid during coupling, and the coupled antigen showed identity with uncoupled native antigen by Ouchterlony analysis. OD values obtained by ELISA showed a log-linear relation to concentration of specific antibody in whole and affinity-chromatographed human sera measured by quantitative precipitation over a range of 0.25 to 3.5 microgram/ml. In replicate ELISA experiments using serially diluted human serum, dilutions with antibody content as low as 0.016 microgram/ml could be reliably differentiated from PBS or agammaglobulinemic serum. The concentration of antibody in 98 selected human sera measured by ELISA correlated well (r = 0.89, p less than 0.001) with results obtained by indirect IF assay. This quantitative ELISA for GBS antibody is rapid, convenient, economical, and suitable for routine use.

Enzyme-Linked Immunosorbent Assay↗
PubMed1981

Antibody response to group B streptococcus type III and AB blood group antigens induced by pneumococcal vaccine.

The effect of pneumococcal vaccination on antibodies to Streptococcus pneumoniae type 14, group B streptococcus type III, and AB blood group antigens was studied in 40 vaccinated adults. Fourfold or greater increases in type-specific IgG antibody to Pn-14 were found in 26 of 40 vaccines (mean increase 6.4-fold) and against GBS-III in 16 of the 40 (mean increase 2.9-fold) by an indirect immunofluorescence assay. However, only six of the 26 vaccinees with low levels (titers less than or equal to 20) of GBS-III antibody in prevaccination sera developed titers greater than 20 after vaccination. Thus, vaccination with polyvalent pneumococcal vaccine does not reliably induce high levels of IF antibody to GBS-III. Fourfold or greater increases in IgG isohemagglutinins against blood group A cells were also found in 22 of 27 vaccines (mean increase 4.5-fold) and against blood group B cells in nine of 34 (mean increase 1.7-fold) using the indirect anti-human globulin test. Chromatographic fractionation of selected sera confirmed that the anti-A isohemagglutinins stimulated in group O subjects were of the IgG class. Thus, pneumococcal vaccination during incompatible pregnancy could potentiate AO hemolytic disease of the newborn infant.

ABO Blood-Group System↗
PubMed1981

Rapid identification of material colonization with group B streptococci by use of fluorescent antibody.

To identify women colonized with group B streptococci during parturition, we used pooled type-specific fluorescent antibody to examine vaginal swabs enriched by preincubation in selective broth medium. In preliminary experiments, group B streptococcus strain III-Bell was reliably detectable with fluorescent antibody at concentrations of greater than 10(5) colony-forming units per ml, achieved after 6 h of incubation of small inocula (18 to 26 colony-forming units). Of the vaginal swabs from 924 parturient women examined prospectively by both fluorescent antibody and selective bacteriology techniques, group B streptococci were isolated in 154. The sensitivity of the fluorescent antibody technique increased with increasing incubation time and ranged from 49% (3 to 6 h) to 81% (7 to 12 h) to 83% (13 to 18 h) to 93% (greater than 18 h). Colonized mothers identified within 6 h by the fluorescent antibody technique had higher rates of vertical transmission to their newborn infants (61%) than colonized mothers whose fluorescent antibody examinations were negative within this time interval (32%; P = 0.027). However, because of the timing of their admissions, none of the colonized mothers of the four infants who developed early-onset group B streptococcal sepsis were identified with fluorescent antibody until after delivery. Although its sensitivity approaches selective culture methods after 6 h of incubation, fluorescent antibody examination of vaginal swabs does not appear to offer a practical approach to identifying colonized parturient women for intrapartum antibiotic prophylaxis of group B streptococcal infection.

Female↗
PubMed1980

Nosocomial transmission of bacteriophage type 7/11/12 group B streptococci in a special care nursery.

Two premature infants in a special care nursery acquired late-onset group B streptococcal (GBS) sepsis within a 24-hour period. The infecting strains were serotype III organisms with bacteriophage type 7/11/12. Cultures of the mothers of the two affected infants were negative for GBS, implying nosocomial acquisition of infection. Although 32% of nursery personnel had mucosal carriage of GBS, none of the seven isolates of GBS type III was the same bacteriophage type as the two infecting strains. Of the other infants hospitalized in the nursery, five were asymptomatically colonized with GBS. These infants were in bassinets adjacent to the affected infants; all five of their isolates were identical to the two infecting strains. We conclude that infant-to-infant transmission may result in nosocomial late-onset GBS septicemia.

Bacteriophage Typing↗
PubMed1980

Metastatic complications of Fusobacterium necrophorum sepsis. Two cases of Lemierre's postanginal septicemia.

We have recently encountered two instances of septicemia due to Fusobacterium necrophorum in adolescents. The presence of severe exudative pharyngitis in both patients pointed to the upper respiratory tract as the probable portal of entry. In one case, metastatic infection was manifested by multiple septic pulmonary emboli with associated pleural effusions. In the other case, diffuse encephalopathy and septic arthritis of the left shoulder and hip occurred. Unilateral neck pain, persistent bacteremia, and prolonged fever despite appropriate antibiotics were consistent with the presence of septic jugular thrombophlebitis in both patients. "Postanginal septicemia" caused by F necrophorum, described by Lemierre in the preantibiotic era, was undoubtedly the syndrome manifested by these patients. This condition, formerly uniformly fatal, can readily be diagnosed when anaerobic techniques are used for blood culture, but requires prolonged antibiotic therapy for cure.

Adolescent↗
PubMed1980

Prevalence of type-specific group B streptococcal antibody in pregnant women.

Immunoglobulin G antibody against the four major serotypes of group B streptococcus was measured by indirect immunofluorescence in the sera of 200 consecutive pregnant women seen in the obstetric screening clinic of an urban teaching hospital. Antibody was detectable in 26% of undiluted sera against serotype Ia, 52% against serotype Ib, 82% against serotype II, and 45% against serotype III. Only 9% had antibody against all four GBS types. When serotype-specific antibody prevalences in 108 women with GBS vaginal colonization were compared with prevalences in noncolonized women, only women colonized with GBS type Ia were more likely to have antibody against Ia than noncolonized women. Antibody prevalences in sera from 54 mothers whose infants developed invasive GBS disease were significantly lower than those in colonized or noncolonized women. Since low titers of IF antibody to GBS III were present in some sera from mothers of infected infants, the data were analyzed based on IF antibody titers associated with passive protection in a chick embryo model of GBS septicemia. None of the sera from mothers of infected infants had antibody levels associated with chick embryo protection. Less than 10% of women had titers associated with chick embryo protection. These data suggest that the majority of pregnant women lack immunity to GBS, regardless of colonization status.

Adult↗
PubMed1980

Histocompatibility antigens and humoral immunity to Epstein-Barr virus.

To explore possible genetic determinants of immunity to Epstein-Barr (EB) virus infection, prevalence rates and geometric mean titers (GMT) of antibody against EB viral capsid antigen (VCA) were measured in 422 adults of known HLA and ABO histocompatibility types. Deviation from the overall prevalence (87%) of anti-VCA titers > 10 was limited to subjects with HLA-A10 (95%) and those with a "blank" HLA-A locus (78%). The latter deviation was largely accounted for by the 13 subjects of HLA-A1/blank constitution (46%). Deviations from the overall mean anti-VCA titer (GMT 131.5) were found in seropositive subjects with blood group 0 (GMT 153.3) and tissue antigens HLA-A3 (GMT 150.8), HLA-B7 (GMT 152.1), HA-Bw15 (GMT 97.0), and HLA-B27 (GMT 86.4). Separate reanalysis of the data for male and female subjects verified the association of blood group 0 with elevated and HLA-B27 with reduced mean levels of anti-VCA antibody.

ABO Blood-Group System↗
PubMed1979

Human immunity to group B streptococci measured by indirect immunofluorescence: correlation with protection in chick embryos.

An indirect immunofluorescence (IF) assay has been developed as a useful semiquantitative method for determination of type-specific IgG antibody in human sera to the five serotypes of group B Streptococcus. Antibody titers measured by IF correlated with passive protection in chick embryos, and antibody titers associated with chick embryo protection were delineated. Except for types Ia and Ic, IF antibody to each of the streptococcal types was completely absorbed by homologous strains, and antibody titers were unchanged by incubation with heterologous bacteria. For types Ia and Ic, IF antibody was absorbed by either the Ia or the Ic strain and by native Ia carbohydrate antigen. Antibody titers measured by IF and chick embryo protection against types Ia and Ic were similar, but were divergent for Ib and Ic, a finding suggesting that antibody is predominantly directed to the major carbohydrate determinants. In addition, 29 of 31 sera that had been tested in chick embryos yielded comparable results in mice against challenge with type Ia group B Streptococcus, a finding further validating the chick embryo assay. Sera from all of 43 mothers of infants infected with group B streptococci had antibody titers by IF that were less than titers associated with protection in chick embryos.

Absorption↗
PubMed1979

Sales of nonprescription cold remedies: a unique method of influenza surveillance.

In 1976, the National Institute of Allergy and Infectious Disease sponsored a nationwide network for influenza surveillance. In this paper, in addition to reporting the surveillance findings in Los Angeles, sales of nonprescription cold remedies in a large supermarket chain were evaluated as an indicator of influenza activity in the community. Twenty-seven isolates of influenza B occurred between February 17 and April 26, 1977. Peak influenza B activity occurred from mid-March to early April, 1977. A 5-10% increase in percent of respiratory and febrile respiratory illness seen in outpatient clinics was observed in late December and January. No variation in these statistics occurred during the peak of influenza activity. In contrast, sales of nonprescription cold remedies were apparently influenced by influenza B activity. Peak sales (345% increase) occurred 4 wk after the first influenza B isolate and 1 wk before peak influenza activity was documented by peak rates of isolation.

Adult↗
PubMed1979

Epidemic measles in young adults. Clinical, epidemiologic, and serologic studies.

An outbreak of measles at the University of California at Los Angeles provided the opportunity to study clinical, epidemiologic, and serologic characteristics of the disease in young adults in the present vaccine era. Of the 34 cases studied, 18 occurred in persons who thought they were immune. Fifteen of 19 seronegative students vaccinated during the epidemic responded with a secondary (IgG) antibody response. Antibody prevalence studies indicated that 91% of the student population had measles antibody at the onset of the outbreak, and history relating to measles correlated poorly with antibody prevalence. Of 212 adults vaccinated, 58% complained of one or more symptoms. Seventeen percent were confined to bed, and in three women vaccine-associated illness was notably severe. That measles will continue to be a problem in adults with our present national approach to immunization is predicted.

Adolescent↗
PubMed1978

Measles revaccination. Persistence and degree of antibody titer by type of immune response.

During a measles immunization campaign 203 children were enrolled in an antibody response study. Of this group, follow-up clinical data and sera samples were available from 125 children three weeks after immunization and from 90 children ten months later. Seventy-six of the children had been previously vaccinated, ten had a history of measles and 39 denied vaccination or illness. Twenty-six of the children had prevaccination hemagglutination inhibiting antibody titers of less than 5. Of this group 12 had a primary immune response (IgM measles antibody) with geometric mean titers (GMT) of 90 and 40 three weeks and ten months respectively after vaccination. In contrast, the other 14 children with initial titers of less than 5 had secondary immune responses (only IgG measles antibody) with GMTs of 28 and 9 three weeks and ten months after vaccination. Since the antibody responses in these children who had previously been stimulated by measles antigen were modest and transient, it is suggested that booster immunization may not be effective in preventing future secondary vaccine failures. Also noted in this study was a poor correlation between historical data and actual measles antibody.

Adolescent↗