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K K Christensen

Publications and source records attributed to K K Christensen.

At least 37 records · Page 2Linked to original sources
PubMed1985

Immune response to pneumococcal vaccine in mothers to infants with group B streptococcal septicemia: evidence for a divergent IgG/IgM ratio.

Eight women who had given birth to infants contracting neonatal septicemia with group B streptococci (GBS) were immunized with a 14-valent pneumococcal vaccine (Pneumovax). Type-specific IgM and IgG antibodies against 6 pneumococcal types were determined before and after vaccination. Ten healthy age-matched women were also vaccinated and served as controls. The study group showed significantly higher preimmune IgM levels against 3 of the 6 pneumococcal antigens, and lower IgG levels against 1 antigen. However, 6 weeks as well as 11/2 years after the immunization, no significant differences in IgG or IgM antibody levels could be demonstrated between the 2 groups. Before vaccination, significantly more study group women showed an arbitrary IgG/IgM ratio below 10 against pneumococcal types 1, 6A, 7F, 14 and 23F. 11/2 years after vaccination, the ratio was significantly lower for antibodies against 2 other types, 6A and 7F. We suggest, as a working hypothesis, that mothers of GBS-infected infants differ in their capacity to switch from IgM to IgG production.

Antibody Formation↗
PubMed1985

Increased frequency of high serum IgM among mothers of infants with neonatal group-B streptococcal septicemia.

Total serum IgM levels were studied in 84 mothers of infants with group-B streptococcal (GBS) septicemia/meningitis and compared to IgM concentrations in 91 parturients who were urogenital carriers of GBS but nevertheless gave birth to healthy infants. In all, 22 (27%) in the study group showed IgM levels above the arbitrarily selected limit of 2.40 g/l, in contrast to 12 (13%) of 91 controls (p = 0.02). Among the study group members whose infants were infected with GBS type III, 8 of 34 (24%) were high in serum IgM, compared to only 2 of 34 (6%) of the corresponding controls (p = 0.04). The total serum IgG levels did not differ between the two groups.

Antibodies, Bacterial↗
PubMed1985

Effects of pneumococcal vaccination on tonsillo-pharyngitis and upper respiratory tract flora.

The effect of a 14-valent pneumococcal vaccine on upper respiratory tract infections and carriage of beta-haemolytic streptococci was studied in a double-blind prospective study of 405 children 0.5-5 years of age. In the children under 2 years of age at vaccination, the cases of acute tonsillitis were more frequent among the vaccinees than among the controls (p less than 0.01). In contrast, among the children over 2 years of age at vaccination, fewer episodes of acute tonsillitis were reported among the vaccinees than among the controls (p less than 0.01). In the older age group, the total rate of upper respiratory tract infections was also significantly reduced. Similarly, an increase in asymptomatic carriage of group A streptococci was registered in children vaccinated at 2-5 years of age (p less than 0.01). Inversely, the carriership of group C streptococci diminished among the vaccinated children (p less than 0.05). Some possible mechanisms underlying these unexpected findings, including non-specific mitogenic features and cross-protection due to antigenic similarities, were explored.

Age Factors↗
PubMed1985

The R-proteins.

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Animals↗
PubMed1985

Reduced colonization of newborns with group B streptococci following washing of the birth canal with chlorhexidine.

Possible measures for prevention of neonatal group B streptococcal (GBS) septicemia include active or passiv immunoprophylaxis and administration of penicillin to mothers and infants. In a previous study we have found GBS to be extremely sensitive to chlorhexidine. Furthermore vaginal washing with chlorhexidine diminished the recovery of GBS from parturients. In order to study the effect of chlorhexidine washing upon the colonization of newborns, a study group of chronic GBS carriers, i.e. women who were GBS positive in the 32-36 gestational week as well as during labor was selected. In 18 of these females chlorhexidine washing was performed prior to delivery while 33 chronic carriers served as controls. Screening during labor was performed in 945 consecutive patients. Cultures were collected from the external ear, throat and umbilicus of all infants within 5 minutes of birth and at day 4 of life. At birth 22% of the infants of the chlorhexidine washed mothers were colonized with GBS, in contrast to 52% of the infants from the chronic GBS carriers (p less than 0.05). The proportion of infants harboring GBS at day 4 were similar in the two groups (Tab. I). Among the 945 consecutively screened women, 164 harbored GBS and 54 (33%) of their 164 infants were colonized at birth. The colonization rate of the infants from chronic GBS carriers was significantly higher, 17 of 33 infants (p less than 0.05). This may reflect that the risk of contracting GBS by infants increases with the quantity of GBS in the birth channel.(ABSTRACT TRUNCATED AT 250 WORDS)

Cervix Uteri↗
PubMed1985

Asymptomatic bacteriuria during pregnancy with special reference to group B streptococci.

The relationship between significant bacteriuria (SB), i.e. 2 subsequent voided urine specimens with greater than or equal to 10(5) colony forming units (CFU)/ml, and the occurrence of bacteria in the urinary bladder detected by bladder punction, was investigated in asymptomatic pregnant women. From 30 (70%) of the 43 women with SB studied, bacteria were isolated from the urinary bladder. The same bacteria were found in the bladders of all 21 women with Escherichia coli, the one with Klebsiella pneumoniae, and the one with Staphylococcus saprophyticus in midstream urine. Six of 10 patients with group B streptococci (GBS), 1 of 4 patients with Streptococcus faecalis, and none of 5 patients with Staphylococcus epidermidis in voided specimens had bacteria in the aspirated urine. Serotype III was isolated from 8/10 patients with SB caused by GBS. One child born to a woman with GBS SB but no bacteria in the urinary bladder, got early onset septicaemia. The poor predictive value of SB with GBS, S. faecalis and S. epidermidis necessitates the increased use of bladder puncture for diagnosis of true asymptomatic bacteriuria (AB), i.e. AB with bacteria in the urinary bladder. SB with GBS even without bacteria in the urinary bladder, may constitute a threat to the baby's health.

Adolescent↗
PubMed1985

Chronic carrier state in mothers of infants with group B streptococcal infections.

Seven of eight women who had given birth to infants with early onset or intrauterine infection caused by group B streptococci remained carriers of the same serotype of group B streptococci up to 38 months after their pregnancy. In contrast, only 34 of 88 group B streptococci carriers who had given birth to healthy infants harbored the same serotype at the 34 months' follow-up (P = .009). Among the control subjects, 29 of 71 showed increased serum levels at followup of antibodies against the serotype isolated at delivery, a significantly higher proportion compared with the mothers of infected infants/fetuses. The results indicate that mothers of group B streptococci-infected infants are chronic urogenital carriers of group B streptococci without responding immunologically against the organism.

Antibodies, Bacterial↗
PubMed1984

Correlation between serum antibody-levels against group B streptococci and gestational age in newborns.

Sera from 33 newborn infants with gestational ages ranging from 27 to 41 weeks were tested by radioimmunoassay for IgG antibodies to surface antigens of group B streptococci (GBS) types Ia, Ib, II and III. Antibody levels to GBS antigens were positively correlated to gestational age and birthweight. However, only the correlations for anti-Ia and anti-II antibody levels reached statistical significance. Mean antibody concentrations in infants below 34 weeks of gestation were significantly lower for type Ia (P less than 0.001), type II (P less than 0.001) and type III (P = 0.05) than in infants above this limit. These findings might explain the higher rate of serious GBS-infections found among prematures as compared to full-term infants.

Antibodies, Bacterial↗
PubMed1984

Intravenous administration of human IgG to newborn infants: changes in serum antibody levels to group B streptococci.

A human IgG preparation was given intravenously to 36 newborn infants admitted to the neonatal intensive care unit because of suspected septicaemia. IgG was given as a single dose of 0.4 g/kg body weight. Patient serum was obtained immediately before and 30 min after terminating the infusion. Blood was also withdrawn 2 days after giving the IgG in eight of the infants. The sera were tested by radioimmunoassay for IgG antibody levels to surface antigens of group B streptococci (GBS) types Ia, Ib, II and III and to R-protein. The mean increases in anti-type Ia, Ib, II, III and R-protein antibodies 30 min after the end of infusion were 81%, 73%, 49%, 60% and 69% of the preinfusion levels, respectively. This was followed by a rapid decrease during the following 2 days to 25%-32% of the initial increases. Based on the above findings, a controlled trial of passive immunisation in the management of neonatal GBS septicaemia seems justified. The rapid decline in antibody levels would necessitate a second infusion 24 h after the initial immunoglobulin administration if the suspicion of septicaemia persists.

Antibodies, Bacterial↗
PubMed1984

Transient increase of early-onset group B streptococcal septicemia.

Since 1976, all cases of neonatal group B streptococcal (GBS) septicemia/meningitis have been registered at two Swedish University Hospitals. A significant increase in the number of infants contracting early-onset GBS-septicemia was noticed at one clinic in 1981, from 1-3 cases per yr to 8 cases. Six months prior to this increase the number of deliveries increased from about 1500 per yr to nearly 3000 per yr. It is suggested that external factors, e.g., subtle changes in the nursing combined with an extended disadvantage at the ward might influence the development of early-onset GBS septicemia.

Humans↗
PubMed1984

Colonisation of the upper respiratory tract of mice with group B streptococci type III with reference to the R-protein.

Nine strains of group B streptococci type III, five with R-protein (R+) and four without (R-) were tested for capacity to colonise the upper respiratory tract in mice and to adhere to human buccal cells. In the mouse model, 80-microliter inocula of dilutions of overnight cultures of the strains in Todd Hewitt broth were placed in the external nares under light ether anaesthesia. A pilot experiment demonstrated that it was reasonable to study the throat colonisation 2 and 4 days after inoculation. Groups of 18-20 mice were then given inocula containing 8 X 10(6) cfu/ml of five R+ and four R- strains. At day 4, significantly more mice were colonised with type III, R+ strains (73% of the animals) than with type III, R- strains (44%) (p less than 0.01). In adherence experiments with human buccal cells, no difference was found between the R+ and R- strains. The results indicated that the higher colonisation rate among R+ strains was mediated by mechanisms other than adherence.

Adhesiveness↗
PubMed1984

Human IgG antibodies to carbohydrate and protein antigens in mouse protection tests with group B streptococci.

The protective effect of four commercial human gammaglobulin batches (I-IV) in mice was studied using six different strains of group B streptococci (GBS): types Ia; Ib; II, R-protein negative (R-); II, R+; III, R-; and III, R+. Each mouse received 1.0 ml gammaglobulin and 0.5 ml bacteria, 10(6)-10(8) colony forming units (CFU). There was a close correlation between antibody levels measured by the use of radiolabeled protein A and the mouse-protective effect of the gamma-globulins. The mouse-protection tests demonstrated that batch I protected against GBS types Ia and III, R- at low concentration (65 mg/kg mouse weight), against type Ib at medium (260 mg/kg) and against type III, R+ at high concentration. Batch IV protected against types Ia and Ib, although the doses were four times higher than those in batch I, but did not protect against type III, R+. There was no mouse protection by any of the batches against type II. Antibody levels against Ibc and R, protein antigens, were substantially lower in batch IV. Because the results of these mouse-protection studies indicate the importance of such antibodies against protein antigens, batches I-III might be more useful for therapy of neonatal GBS-septicemia.

Animals↗
PubMed1983

The significance of group B streptococci in neonatal pneumonia.

Thirty-eight infants admitted to a neonatal intensive care unit because of pneumonia (14 patients) and pulmonary maladaption syndrome (PMA) (24 patients) were included in the study. Samples of potentially pathogenic, facultatively anaerobic bacteria were taken from the external ear, blood, throat, nasopharynx, umbilicus and gastric aspirates of the children, and from urethra and cervix of the mothers. Group B streptococci (GBS) and Escherichia coli were the only potentially pathogenic bacteria isolated from the infants. Out of 14 infants with pneumonia 11 (79%) harboured one of these bacteria, in contrast to 3 out of 24 (13%) with PMA (P less than 0.001). GBS was found in 8/14 infants with pneumonia and in 1/24 infants with PMA (P less than 0.001). The respective frequencies for Escherichia coli were 3/14 and 2/24 (not significant). The infant and/or the mother in 10/14 pneumonia cases harboured GBS, in contrast to 4/24 pairs in the PMA group (P less than 0.001). The levels of antibodies against GBS in sera of mothers to infants with pneumonia did not differ from the antibody levels in control sera (parturient GBS-carriers giving birth to healthy infants). The results gave evidence for an important manifestation of neonatal GBS-infection: pneumonia without septicemia. The incidence of the disease is estimated to be 1:25 parturient GBS-carriers. Finally, maternal fever, gestational age above 42 weeks, more severe respiratory difficulties and the occurrence of severe changes in fetal heart rate during the first stage of labour were found to be typical characteristics of pneumonia, as compared to PMA.

Escherichia coli↗
PubMed1983

Chlorhexidine for prevention of neonatal colonization with group B streptococci. I. In vitro effect of chlorhexidine on group B streptococci.

Forty-three strains of group B streptococci (GBS) of types Ia, Ib, II and III were tested for susceptibility to chlorhexidine in concentrations ranging from 256 to 0.25 mg/l using the agar and tube dilution methods. The strains showed minimum inhibitory concentration (MIC) values ranging from 0.5 to 1 mg/l. Serum added to the test medium (50%) increased the MIC values to 4-8 mg/l, while amniotic fluid (50%) had almost no effect, increasing the values to 1-2 mg/l. The minimum bactericidal concentration (MBC) ranged from 1 to 5 mg/l. The killing kinetics were related to the concentration of chlorhexidine and the length of exposure. For example, at a concentration of 63 mg/l, 7 h were required for a bactericidal effect in broth, as compared to 1 h at 500 mg/l chlorhexidine. 200 mg/l chlordexidine had no effect on the adherence of two GBS strains to vaginal epithelial cells, and no effect on the phagocytosis of GBS with mouse peritoneal macrophages.

Bacteriolysis↗