Search PubMed⌕ Search

Biomedical subjects

R S Gibbs

Publications and source records attributed to R S Gibbs.

At least 37 records · Page 2Linked to original sources
PubMed1995

Association between bacterial vaginosis and preterm delivery of a low-birth-weight infant. The Vaginal Infections and Prematurity Study Group.

BACKGROUND: Bacterial vaginosis is believed to be a risk factor for preterm delivery. We undertook a study of the association between bacterial vaginosis and the preterm delivery of infants with low birth weight after accounting for other known risk factors. METHODS: In this cohort study, we enrolled 10,397 pregnant women from seven medical centers who had no known medical risk factors for preterm delivery. At 23 to 26 weeks' gestation, bacterial vaginosis was determined to be present or absent on the basis of the vaginal pH and the results of Gram's staining. The principal outcome variable was the delivery at less than 37 weeks' gestation of an infant with a birth weight below 2500 g. RESULTS: Bacterial vaginosis was detected in 16 percent of the 10,397 women. The women with bacterial vaginosis were more likely to be unmarried, to be black, to have low incomes, and to have previously delivered low-birth-weight infants. In a multivariate analysis, the presence of bacterial vaginosis was related to preterm delivery of a low-birth-weight infant (odds ratio, 1.4; 95 percent confidence interval, 1.1 to 1.8). Other risk factors that were significantly associated with such a delivery in this population were the previous delivery of a low-birth-weight infant (odds ratio, 6.2; 95 percent confidence interval, 4.6 to 8.4), the loss of an earlier pregnancy (odds ratio, 1.7; 1.3 to 2.2), primigravidity (odds ratio, 1.6; 1.1 to 1.9), smoking (odds ratio, 1.4; 1.1 to 1.7); and black race (odds ratio, 1.4; 1.1 to 1.7). Among women with bacterial vaginosis, the highest risk of preterm delivery of a low-birth-weight infant was found among those with both vaginal bacteroides and Mycoplasma hominis (odds ratio, 2.1; 95 percent confidence interval, 1.5 to 3.0). CONCLUSIONS: Bacterial vaginosis was associated with the preterm delivery of low-birth-weight infants independently of other recognized risk factors.

Cohort Studies↗
PubMed1995

Outcome of the Vaginal Infections and Prematurity Study: results of a clinical trial of erythromycin among pregnant women colonized with group B streptococci.

OBJECTIVE: Our purpose was to determine whether erythromycin treatment of pregnant women colonized with group B streptococci would reduce the occurrence of low birth weight (< 2500 gm) and preterm (< 37 completed weeks) birth. STUDY DESIGN: In a double-blind clinical trial, 938 carriers of group B streptococci were randomized to receive erythromycin base (333 mg three times a day) or matching placebo beginning during the third trimester and before 30 weeks and continuing for 10 weeks or until 35 weeks 6 days of pregnancy. RESULTS: Pregnancy outcomes were available for 97% of randomized women; 14% of subjects withdrew from the trial. Birth weight < 2500 gm occurred in 8.6% of the erythromycin and 6.1% of the placebo recipients (relative risk 1.4, 0.9 to 2.2, p = 0.16). Preterm delivery occurred in 11.4% of women randomized to erythromycin and in 12.3% randomized to placebo (relative risk 0.9, 95% confidence limits 0.6 to 1.3, p = 0.65). Greater benefit of erythromycin in reducing these outcomes was not observed among women reporting the best compliance. CONCLUSIONS: In this study of pregnant women colonized with group B streptococci treatment with erythromycin was not shown to be effective at prolonging gestation or reducing low birth weight. Greater than anticipated complicating factors, including spontaneous clearance of the organism, use of nontrial antibiotics, and density of colonization, may have resulted in population sizes too small to detect a benefit of treatment. Future studies should take these factors into account in determining sample sizes.

Adult↗
PubMed1995

The genital flora of women with intraamniotic infection. Vaginal Infection and Prematurity Study Group.

The relationship of genital flora assessed at the end of the second trimester of pregnancy and intraamniotic infection diagnosed by clinical signs and symptoms during labor was evaluated. Women were enrolled at 23-26 weeks of gestation and followed through delivery in the multi-center Vaginal Infections and Prematurity Study (1984-1989). Among the cohort of 11,989 followed through delivery, 286 (2.4%) developed intraamniotic infection. The recovery of Gardnerella vaginalis (relative risk [RR] = 1.8; 95% confidence interval [CI] = 1.4-2.4), heavy growth of Bacteroides species (RR = 1.5; 95% CI = 1.1-2.1), and isolation of Mycoplasma hominis (RR = 1.7; 95% CI = 1.3-2.1) from the vagina at the end of the second trimester of pregnancy were associated with an increased risk of intraamniotic infection. Bacterial vaginosis was also associated with intraamniotic infection (RR = 1.5; 95% CI = 1.1-2.2). These findings extend prior studies by showing that prenatal cultures for microorganisms associated with bacterial vaginosis predicted an increased risk of intraamniotic infection.

Adolescent↗
PubMed1995

Women's reasons for not seeking prenatal care: racial and ethnic factors.

Our objective was to determine if there were differences in the reasons for not seeking early prenatal care among low-income black, Hispanic, and white women who had four or fewer prenatal care visits or care only in the third trimester, and who gave birth at Denver General Hospital in Colorado. Data were gathered from 606 women (48% Hispanic, 26% black, 26% white) after delivery, using a 188-item questionnaire and abstracted medical charts. The most important reasons for not seeking early prenatal care were attitudinal (47%), financial (26%), and structural and system problems (8.5%). Financial reasons were more important to white than to black or Hispanic women, and attitudinal reasons were more important to black and Hispanic than to white women. The analysis showed that education and marital status were sometimes confounding variables. Clear differences in reasons for not seeking prenatal care were reported by women of dissimilar racial and ethnic groups in this public hospital. Cultural variations in women's views should be taken into account in developing programs intended to improve prenatal care and pregnancy outcome in Denver.

Adult↗
PubMed1994

A survey of practices in infectious diseases by obstetrician-gynecologists.

OBJECTIVE: To survey current practices among obstetricians and gynecologists concerning a wide range of infectious diseases to guide future efforts in continuing medical education. METHODS: A survey questionnaire of multiple-choice questions was mailed to 2500 physicians, under age 65, randomly selected from the American Medical Association specialty list of obstetrician-gynecologists. The first 500 returns constituted the data set and were analyzed by computer. RESULTS: We found many clinical areas in which practice patterns were deemed appropriate, including antibiotic selection, universal screening for hepatitis B, and follow-up of urinary tract infection in pregnancy. In other areas, marked by controversy among "experts," practice patterns varied widely. These areas included management of premature rupture of the membranes and premature labor, and universal screening for group B streptococci. Areas in need of further continuing medical education efforts include management of perinatal viral infections and diagnosis and treatment of sexually transmitted diseases. CONCLUSIONS: Although this survey indicated that practice patterns of American obstetricians and gynecologists are appropriate in many clinical areas relevant to infectious diseases, there are other clinical conditions requiring future efforts in continuing medical education.

Female↗
PubMed1994

Randomized comparison of ampicillin-sulbactam to cefoxitin and doxycycline or clindamycin and gentamicin in the treatment of pelvic inflammatory disease or endometritis.

OBJECTIVE: To evaluate the efficacy and safety of ampicillin-sulbactam (3 g every 6 hours) in patients with pelvic inflammatory disease or postpartum endometritis using a randomized, comparative, multicenter study of parallel design. METHODS: Eligible patients with pelvic inflammatory disease were randomized to receive either ampicillin-sulbactam or cefoxitin (2 g every 6 hours) plus doxycycline (100 mg every 12 hours). Those with endometritis were randomized to ampicillin-sulbactam or clindamycin (900 mg every 8 hours) plus gentamicin (1.5 mg/kg every 8 hours). In the ampicillin-sulbactam group, chlamydia-positive patients also received oral doxycycline. RESULTS: For pelvic inflammatory disease, the clinical response rates (cure or improvement) were 85.5% (47 of 55) and 89.6% (43 of 48) in the ampicillin-sulbactam and cefoxitin and doxycycline groups, respectively (chi 2 = 0.10, P = .76). For endometritis, the clinical response rates were 88.7% (141 of 159) and 90.8% (139 of 153) in the ampicillin-sulbactam and clindamycin and gentamicin groups, respectively (chi 2 = 0.15, P = .70). The percentages of patients with pelvic inflammatory disease who had adverse experiences were not significantly different in the cefoxitin and doxycycline group (47% [29 of 62]) than in those receiving ampicillin-sulbactam (33% [22 of 66]) (P = .12). These adverse effects were mostly mild or moderate. In the endometritis subjects, the incidence of adverse experiences in the ampicillin-sulbactam group (11% [20 of 179]) was comparable to that during treatment with clindamycin and gentamicin (12% [22 of 180]). These adverse experiences were also mostly mild to moderate. CONCLUSION: Ampicillin-sulbactam is as effective and well tolerated as combination regimens using cefoxitin plus doxycycline and clindamycin plus-gentamicin for the treatment of pelvic inflammatory disease or endometritis, respectively.

Adult↗
PubMed1994

Is penicillin G a better choice than ampicillin for prophylaxis of neonatal group B streptococcal infections?

A review of the pharmacokinetics and the narrow spectrum of action of penicillin G favors this antibiotic over ampicillin for the prophylaxis of early neonatal group B streptococcal (GBS) disease. Penicillin G provides good placental transfer and fetal and neonatal tissue levels. Group B streptococcal disease has a narrower range of sensitivities to penicillin G than to ampicillin, and the potential for selecting more resistant organisms may be greater with the broader spectrum of ampicillin than with penicillin G.

Ampicillin↗
PubMed1994

Neonatal group B streptococcal sepsis during 2 years of a universal screening program.

OBJECTIVE: To assess the feasibility and efficacy of a protocol for universal screening for group B streptococci combined with selective intrapartum prophylaxis at a teaching hospital. METHODS: This is a descriptive study of experience with a standardized protocol in which patients were screened at 26-28 weeks with a rectal and genital culture placed directly in selective media. As risk factors, we used clinical chorioamnionitis, preterm birth, and rupture of the membranes greater than 12 hours. Participants were all women receiving prenatal care at our hospital. Major outcomes were compliance and neonatal sepsis due to group B streptococci. RESULTS: The prevalence of rectal and genital group B streptococci was 18.5% of 3721 screened women. Of culture-positive women, 35% developed risk factors (9% chorioamnionitis, 13% preterm birth, and 13% membrane rupture greater than 12 hours at term). With strict application of criteria, the compliance rate in administering indicated prophylaxis was 80.3%. Of women receiving prophylaxis, 42% had the first dose for 4 hours or less before delivery. There were five cases of group B streptococcal neonatal sepsis, resulting from either protocol violations, protocol failures, or both. Compared to the historic rate of group B streptococcal sepsis of 1.5 per 1000 births at our hospital, the rate in these 2 years was 1.0 per 1000 (1.6 per 1000 in the first year and 0.5 per 1000 in the second). CONCLUSIONS: It is feasible to conduct such a protocol, but compliance is only moderately good because the algorithm is complex. The protocol is not foolproof in preventing neonatal group B streptococcal sepsis, as there are protocol failures and violations.

Adult↗
PubMed1993

Chorioamnionitis and bacterial vaginosis.

An improved understanding of bacterial vaginosis and of clinical intraamniotic infection and histologic chorioamnionitis has produced data showing strong associations among these conditions. It has recently been shown that the microorganisms in both bacterial vaginosis and clinical intraamniotic infection are similar, of which anaerobes, Gardnerella vaginalis, and Mycoplasma hominis are the predominant organisms in both. Furthermore, in the amniotic fluid of women with intraamniotic infection, strong associations among anaerobes, G. vaginalis, and M. hominis have recently been observed. In two epidemiologic studies (one in a high-risk group of women in labor and another in a lower risk group of antepartum women), the presence of bacterial vaginosis has been associated with the development of intraamniotic infection. Additional recent studies have provided new evidence that histologic inflammation of the placental membranes is associated with both clinical intraamniotic infection and positive cultures of the placenta. Multiple logistic regression analysis has shown a relationship between isolation of organisms from the chorioamnion and bacterial vaginosis.

Chorioamnionitis↗
PubMed1993

A rabbit model for ascending infection in pregnancy: intervention with indomethacin and delayed ampicillin-sulbactam therapy.

OBJECTIVE: In a modified pregnant rabbit model using intracervical inoculation of Escherichia coli we investigated the effects of administration of delayed antibiotics and indomethacin on outcomes. STUDY DESIGN: We inoculated 10(5) colony-forming units of Escherichia coli or saline solution bilaterally in the cervix of New Zealand White rabbits at 70% of gestation and assigned animals to ampicillin-sulbactam therapy beginning at 0, 4, 8, 12, and 16 hours after inoculation with Escherichia coli or to no antibiotic therapy. We alternated indomethacin pretreatment in rabbits receiving no antibiotic therapy and rabbits starting ampicillin-sulbactam 4 hours after inoculation. RESULTS: Compared with saline solution inoculated control animals, those inoculated with Escherichia coli (and given no antibiotic therapy) had significant increases in fetal loss, fever, bleeding at 24 hours, and positive cultures (100%, 92%, 76%, 98% versus 0%, respectively, all p < 0.01). In Escherichia coli-inoculated animals receiving no antibiotic therapy pretreatment with indomethacin significantly decreased bleeding and delivery within first 24 hours compared with those not treated with indomethacin (p < 0.05) but did not significantly improve fetal survival. Ampicillin-sulbactam treatment stated at 0, 4, 8, and 12 hours after inoculation resulted in improved fetal survival compared with the untreated group (100%, 56%, 50%, 50% versus 0%, respectively, all p < 0.05). Treatment initiated at 16 hours resulted in outcomes similar to Escherichia coli-inoculated animals receiving no antibiotic therapy. CONCLUSION: Intracervical Escherichia coli inoculation produced infection in the uterus and uniform pregnancy loss. Pretreatment with indomethacin did not result in improved fetal survival. Ampicillin-sulbactam therapy, initiated as long as 12 hours after Escherichia coli inoculation, resulted in significant improvement in fetal survival compared with antibiotic therapy. We believe this model mimics ascending infection in pregnancy more closely than do previous animal models.

Ampicillin↗
PubMed1993

Adverse perinatal outcome and resistant Enterobacteriaceae after antibiotic usage for premature rupture of the membranes and group B streptococcus carriage.

OBJECTIVE: To report a case series of adverse perinatal outcomes associated with resistant Enterobacteriaceae after antibiotic usage for premature rupture of the membranes (PROM) and group B streptococcus. METHODS: Maternal and neonatal records were reviewed of four cases in which adverse perinatal outcomes occurred from resistant Enterobacteriaceae after antibiotic usage for either PROM or positive group B streptococcal cultures. Information on clinical setting, antibiotic usage, maternal and neonatal complications, and maternal and neonatal cultures was noted. RESULTS: All four cases were complicated by PROM at 25-35 weeks' gestation. Ampicillin or amoxicillin was used in several clinical settings, including therapeutically for the presence of group B streptococcus, presumptively for PROM, and prophylactically pending the results of group B streptococcal cultures. Clinical chorioamnionitis subsequently developed in all four cases, and in two cases the maternal course was prolonged and complicated by persistent fever and the need for therapy for pelvic vein thrombophlebitis. Two neonates died from fulminant clinical sepsis. A third infant, one of a twin gestation, was stillborn, presumably because of sepsis. In three cases, neonatal and placental cultures revealed Escherichia coli resistant to ampicillin; in the fourth case, Klebsiella pneumoniae was identified, with only intermediate sensitivity to ampicillin. CONCLUSION: Resistant Enterobacteriaceae associated with adverse perinatal outcomes may result from the use of antibiotics, such as ampicillin or amoxicillin, after PROM. In deciding whether antibiotic therapy for PROM or group B streptococcal prophylaxis is appropriate, the value of purported benefits must be weighed against presumably infrequent but serious outcomes, including neonatal sepsis and death due to selection or overgrowth of resistant organisms.

Amoxicillin↗
PubMed1992

Characteristics of three vaginal flora patterns assessed by gram stain among pregnant women. Vaginal Infections and Prematurity Study Group.

This study was undertaken to define the characteristics and persistence of vaginal flora in 7918 pregnant women at 23 to 26 weeks' gestation. Vaginal smears were categorized as normal (predominant lactobacilli), intermediate (reduced lactobacilli), or positive for bacterial vaginosis. The women with normal flora were least likely to have elevated vaginal pH, amine odor, milky discharge, or colonization by Gardnerella, Bacteroides, or genital mycoplasmas. Women with intermediate vaginal flora had intermediate frequencies of these clinical signs and microorganisms. Group B streptococci and yeast were associated with normal or intermediate flora, whereas Neisseria gonorrhoeae and Chlamydia trachomatis were recovered more frequently from women with intermediate flora or bacterial vaginosis. Trichomonas vaginalis was most associated with intermediate flora. At follow-up, 81% of the women with normal flora had remained normal. Of the women with intermediate flora, 32% acquired bacterial vaginosis and 30% shifted to normal flora. Only 12% of the women with bacterial vaginosis had shifted to normal flora. We conclude that there are two primary stable vaginal flora patterns (normal flora or bacterial vaginosis) and a third less distinct transitional flora pattern between these two.

Adolescent↗
PubMed1992

A review of premature birth and subclinical infection.

Premature birth causes high rates of neonatal morbidity and mortality. There are multiple causes of preterm birth. This article reviews the evidence linking subclinical infection and premature birth. Although maternal genital tract colonization with specific organisms has been inconsistently associated with preterm birth and/or premature rupture of membranes, some infections have been consistently associated with preterm delivery. The association of histologic chorioamnionitis with prematurity is a consistent finding, but the mechanisms require further study. The relationship between histologic chorioamnionitis infection and the chorioamnionitis of prematurity requires additional research. A varying number of patients in "idiopathic" preterm labor have positive amniotic fluid cultures (0% to 30%), but it is not clear whether infection preceded labor or occurred as a result of labor. Evidence of subclinical infection as a cause of preterm labor is raised by finding elevated maternal serum C-reactive protein and abnormal amniotic fluid organic acid levels in some patients in preterm labor. Biochemical mechanisms for preterm labor in the setting of infection are suggested by both in vitro and in vivo studies of prostaglandins and their metabolites, endotoxin and cytokines. Some, but by no means all, antibiotic trials conducted to date have reported decreases in prematurity. These results support the hypothesis that premature birth results in part from infection caused by genital tract bacteria. In the next few years, research efforts must be prioritized to determine the role of infection and the appropriate prevention of this cause of prematurity.

Anti-Bacterial Agents↗
PubMed1992

Amniotic fluid tumor necrosis factor-alpha and interleukin-1 in a rabbit model of bacterially induced preterm pregnancy loss.

OBJECTIVE: The objective of this study was to determine whether the cytokines tumor necrosis factor-alpha, interleukin-1 alpha, and interleukin-1 beta were produced in the amniotic fluid of the rabbit after intracervical inoculation with Escherichia coli. STUDY DESIGN: Timed pregnant rabbits on day 21 (70% of gestation) were inoculated with a hysteroscope intracervically with 10(4) to 10(5) colony-forming units Escherichia coli or sterile saline solution. Escherichia coli-inoculated animals (N = 16) were put to death at 4, 8, 12, and 16 hours after inoculation. Control animals (N = 6) were put to death at similar intervals. At death, cultures were taken from endometrium, amniotic fluid, peritoneum, and blood. Amniotic fluid was collected and assayed for tumor necrosis factor bioactivity by a modified fibroblast cytotoxic assay in L929 cells, for interleukin-1 alpha, and interleukin-1 beta with a specific radioimmunoassay, and for prostaglandin E2 and prostaglandin F2 alpha by radioimmunoassay. RESULTS: Levels of amniotic fluid tumor necrosis factor-alpha, interleukin-1 alpha, and interleukin-1 beta were elevated as early as 4 hours after inoculation in some animals and by 12 to 16 hours after inoculation in all. Levels of all three cytokines correlated significantly with time from intracervical inoculation with Escherichia coli (p < 0.05). Levels of amniotic fluid prostaglandin E2 and prostaglandin F2 alpha correlated significantly with time from intracervical inoculation with Escherichia coli (p < 0.05). CONCLUSIONS: Levels of tumor necrosis factor-alpha, interleukin-1 alpha, interleukin-1 beta, prostaglandin E2 and prostaglandin F2 alpha are elevated in the amniotic fluid of rabbits after intracervical inoculation with Escherichia coli. Similarity exists between elevations of amniotic fluid cytokines in this model and in cases of intraamniotic infection and preterm labor unresponsive to tocolytics in humans. Modulation of cytokines may offer a strategy for improvement of outcome in this experimental model of infection-induced pregnancy loss.

Abortion, Veterinary↗
PubMed1992

Polymerase chain reaction-based genotyping for allotypic markers of immunoglobulin kappa shows allelic association of Km with kappa variable segment.

Allotypic markers of immunoglobulin kappa (Km) may be determined using a novel method of amplification of the constant segment (C kappa) (IGKC) by polymerase chain reaction (PCR) followed by restriction enzyme digestion. Restriction sites in the C kappa PCR product correlate with allotypic differences among Km(1), Km(1,2), and Km(3) alleles. An AccI site in the PCR product correlates with Km(3); and presence or absence of a MaeII site correlates with the Km(1) or Km(1,2) allele, respectively. Km allelic frequencies were determined in a Caucasian population and compared to genotypic frequencies of nearby polymorphic markers. Among unrelated individuals with rheumatoid arthritis (RA) and controls, there is no evidence of allelic association between CD8A and polymorphic markers of the immunoglobulin kappa region [a V kappa (IGKV) BglII polymorphism about 24 kb centromeric to C kappa, Km allotype, and a SacI polymorphism 3.5 kb telomeric to the C kappa segment]. Similarly, there is no allelic association of the SacI C kappa polymorphism with Km or with the BglII V kappa polymorphism. However, there is evidence of allelic association of V kappa B3 and Km, specifically between the V kappa BglII 2.2-kb allele and Km(3) and also between the V kappa 3.5-kb allele and Km(1,2). Therefore, Km typing by PCR-based methods suggests the presence of allelic association between polymorphisms within the coding region of the C kappa segment and the nearest V kappa segment.

Alleles↗