Biomedical subjects

M A Krohn

Publications and source records attributed to M A Krohn.

17 recordsLinked to original sources

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

The association of occult amniotic fluid infection with gestational age and neonatal outcome among women in preterm labor.

To evaluate the relationships between gestational age, neonatal outcome, and amniotic fluid (AF) bacteria, we obtained AF from women with intact membranes in idiopathic preterm labor. Positive cultures were obtained from 20 (19%) of 105 women. The frequency of positive cultures was inversely related to gestational age: 23-26 weeks, nine of 20; 27-30 weeks, four of 24; and 31-34 weeks, seven of 61 (chi2 for trend, P less than .001). Fusobacterium nucleatum, Bacteroides ureolyticus, and Ureaplasma urealyticum were the most common isolates. Facultative and anaerobic bacteria were more commonly isolated from women at less than 30 weeks' gestation, and Ureaplasma urealyticum was commonly isolated at greater than 30 weeks' gestation. Forty percent of the patients identified as having positive AF facultative and anaerobic cultures by the research laboratory had negative cultures in the clinical laboratory. Clinical characteristics and maternal white blood cell count and differential did not differ between women with and without positive cultures. Elevated C-reactive protein levels and a positive AF Gram stain were the two most sensitive and specific methods to predict positive AF cultures. Women with positive cultures delivered a median of 1.0 day after enrollment, compared with 28.5 days for women with negative cultures. The median gestational age at delivery for women with positive cultures was 27.5 weeks, and the median birth weight was 866 g. Positive AF cultures were associated with respiratory distress syndrome, bronchopulmonary dysplasia, and neonatal death. If occult AF infection among women in preterm labor is a treatable cause of preterm birth, then treatment could markedly reduce both perinatal morbidity and mortality.

Amniotic Fluid↗

PubMed1992

The relationship of hydrogen peroxide-producing lactobacilli to bacterial vaginosis and genital microflora in pregnant women.

Lactobacilli provide an important microbial defense against genital colonization by pathogens. The role of hydrogen peroxide (H2O2) in the control of genital microflora was explored in a cross-sectional study of 275 women in the second trimester of pregnancy. Vaginal cultures were obtained for detection of H2O2-positive and H2O2-negative lactobacilli and other members of the genital microflora. Compared with women with H2O2-negative lactobacilli, women colonized by H2O2-positive lactobacilli were less likely to have bacterial vaginosis, symptomatic candidiasis, and vaginal colonization by Gardnerella vaginalis, Bacteroides, Peptostreptococcus, Mycoplasma hominis, Ureaplasma urealyticum, and viridans streptococci (P less than or equal to .05 for each comparison). In addition to the above organisms, women without vaginal lactobacilli were more likely than those women with H2O2-positive lactobacilli to have Chlamydia trachomatis, and less likely to be colonized by Enterococcus or coagulase-negative staphylococci (P less than .05 for each comparison). Vaginal colonization by group B streptococci or Escherichia coli was not related to the presence of H2O2-positive lactobacilli. These data suggest that the presence of H2O2-positive lactobacilli in the vagina is inversely correlated with infection by some genital pathogens in pregnant women.

Bacteria↗

PubMed1991

Microbiologic causes and neonatal outcomes associated with chorioamnion infection.

Chorioamnion infection is associated with histologic chorioamnionitis and prematurity, but the specific chorioamnion microorganisms associated with histologic chorioamnionitis, prematurity, and poor neonatal outcome have not been identified. Bacteria were recovered from the chorioamnion cultures of 32% of 112 placentas delivered at less than or equal to 34 weeks' gestation and from 19% of 156 placentas delivered at greater than 34 weeks' gestation (odds ratio 2.1; 95% confidence interval 1.1 to 3.8). Chorioamnion bacteria most highly related to both prematurity and histologic chorioamnionitis were group B Streptococcus and Fusobacterium species. Chorioamnion infection with Peptostreptococcus was significantly related only to preterm delivery, and infection with Escherichia coli, Bacteroides, and Ureaplasma were significantly related to histologic chorioamnionitis. Among preterm infants, isolation of bacteria from the chorioamnion was related to an increased risk of neonatal death (rate ratio 3.8; 95% confidence interval 1.4 to 11.6). Bacterial infection of the chorioamnion is related to preterm birth, histologic chorioamnionitis, and neonatal death.

Adolescent↗

PubMed1991

Vaginal Bacteroides species are associated with an increased rate of preterm delivery among women in preterm labor.

The relationship of high concentrations of vaginal microorganisms with an increased rate of preterm delivery (less than or equal to 34 weeks) among women in preterm labor was evaluated. Quantitative vaginal cultures were obtained from 211 women in preterm labor between gestational ages of 22 and 34 completed weeks. Preterm delivery occurred in 139 (66%). The rate of preterm delivery was determined by Cox proportional hazards models. Women with greater than 10(7) cfu/ml of vaginal fluid of facultative lactobacilli had a 40% decreased rate of preterm delivery (rate ratio [RR] = 0.6, 95% confidence interval (CI) = 0.4-0.9). An increased rate of preterm delivery occurred among women with Bacteroides bivius at concentrations of greater than 10(4) cfu/ml (RR = 2.0, 95% CI = 1.4-2.9) and Bacteroides fragilis (RR = 1.7, 95% CI = 1.0-2.8). Other microorganisms, including Gardernella vaginalis, the genital mycoplasmas, group B streptococci, Escherichia coli, and Peptostreptococcus species, were not associated with an increased rate of preterm delivery for women in preterm labor.

Adolescent↗

PubMed1991

C-reactive protein in normal pregnancy.

Maternal serum C-reactive protein (CRP) has been studied extensively as an adjunct in the diagnosis of subclinical infection among pregnant women with preterm labor or preterm rupture of membranes. However, before the utility of CRP can be studied in pregnancies with these complications, the effects of normal pregnancy and labor on maternal serum CRP levels must be established. We determined CRP levels serially from 22 weeks' gestation until delivery in healthy pregnant women without antepartum complications. Median CRP values for women not in labor ranged from 0.7-0.9 mg/dL, depending on gestational age; 95% of the values were 1.5 mg/dL or lower. No consistent change in CRP levels with gestational age was found among serially sampled women not in labor. The median CRP value for women in labor at term was 1.3 mg/dL, and 32% of values were over 1.5 mg/dL. Median CRP values in normal pregnancies appear to be higher than standardized values for nonpregnant individuals, and CRP values are further elevated in labor. Understanding the physiology and temporal course of the increase in CRP in normal pregnancy and labor may help to clarify the appropriate use of CRP in complicated pregnancies.

Adolescent↗

PubMed1991

Reliability of diagnosing bacterial vaginosis is improved by a standardized method of gram stain interpretation.

The purpose of the study was to examine intercenter variability in the interpretation of Gram-stained vaginal smears from pregnant women. The intercenter reliability of individual morphotypes identified on the vaginal smear was evaluated by comparing them with those obtained at a standard center. A new scoring system that uses the most reliable morphotypes from the vaginal smear was proposed for diagnosing bacterial vaginosis. This scoring system was compared with the Spiegel criteria for diagnosing bacterial vaginosis. The scoring system (0 to 10) was described as a weighted combination of the following morphotypes: lactobacilli, Gardnerella vaginalis or bacteroides (small gram-variable rods or gram-negative rods), and curved gram-variable rods. By using the Spearman rank correlation to determine intercenter variability, gram-positive cocci had poor agreement (0.23); lactobacilli (0.65), G. vaginalis (0.69), and bacteroides (0.57) had moderate agreement; and small (0.74) and curved (0.85) gram-variable rods had good agreement. The reliability of the 0 to 10 scoring system was maximized by not using gram-positive cocci, combining G. vaginalis and bacteroides morphotypes, and weighting more heavily curved gram-variable rods. For comparison with the Spiegel criteria, a score of 7 or higher was considered indicative of bacterial vaginosis. The standardized score had improved intercenter reliability (r = 0.82) compared with the Spiegel criteria (r = 0.61). The standardized score also facilitates future research concerning bacterial vaginosis because it provides gradations of the disturbance of vaginal flora which may be associated with different levels of risk for pregnancy complications.

Bacterial Infections↗

PubMed1991

Amoxicillin treatment of bacterial vaginosis during pregnancy.

The purpose of this investigation was to evaluate the efficacy of amoxicillin for treatment of bacterial vaginosis during pregnancy. The diagnosis of bacterial vaginosis was established by clinical examination and microscopic examination of a Gram stain and saline preparation of vaginal secretions. In a double-blind, randomized manner, 108 patients at 15-25 weeks' gestation were assigned to treatment with oral amoxicillin, 500 mg three times daily for 14 days, or placebo. Patients were evaluated 2 weeks after treatment, at 34-36 weeks' gestation, and at delivery. There were no significant differences between the two groups with respect to any clinical or microbiologic measure of treatment outcome. There were also no significant differences in the frequency of obstetric complications. We conclude that amoxicillin is not effective therapy for bacterial vaginosis in pregnant women.

Amoxicillin↗

PubMed1990

Bacterial vaginosis as a risk factor for post-cesarean endometritis.

Bacterial species associated with bacterial vaginosis have been isolated more frequently from endometrial cultures of patients with postpartum endometritis than expected from the prevalence of bacterial vaginosis among pregnant women. To further assess the association between bacterial vaginosis and postpartum endometritis, vaginal Gram smears were obtained from women admitted for delivery. Vaginal smears of women delivered by cesarean were scored as normal or as indicating bacterial vaginosis. Factors related independently to postpartum endometritis by multiple logistic regression analysis included maternal age less than 25 years, any duration of membrane rupture, and bacterial vaginosis. The unadjusted odds ratio for the development of postpartum endometritis associated with bacterial vaginosis (odds ratio = 6.1, 95% confidence interval 3.3-15.9) was not appreciably changed in the multivariable analysis (odds ratio = 5.8, 95% confidence interval 3.0-10.9) after adjusting for maternal age, duration of labor, and duration of membrane rupture. At the time of endometritis, Bacteroides sp, Peptostreptococcus sp, and Gardnerella vaginalis were isolated more frequently from the endometrium using a triple lumen endometrial sampling method among patients with bacterial vaginosis than among those with a normal Gram stain. Bacterial vaginosis appears to be an important risk factor for postpartum endometritis after cesarean delivery.

Adult↗

PubMed1990

The relationship of abruptio placentae with maternal smoking and small for gestational age infants.

A population-based case-control study was conducted to examine the relationship between maternal smoking and the occurrence of abruptio placentae and to assess the joint relationship of smoking and small for gestational age (SGA) status with abruption. Cases (N = 1089) reported on Washington state birth certificates from 1984-1986 were compared with randomly selected births (N = 2323) from the same period. The occurrence of placental abruption was associated with both smoking (relative risk = 1.6; 95% confidence interval 1.3-1.8) and SGA status (relative risk = 2.6; 95% confidence interval 2.0-3.3). The association with SGA status was identical for smokers and non-smokers. Thus, the increase of SGA infants in women whose pregnancies are complicated by abruption is not explained by maternal smoking, and in some cases may result from placental dysfunction induced by the process of placental separation.

Abruptio Placentae↗

PubMed1990

Microbiologic efficacy of intravaginal clindamycin cream for the treatment of bacterial vaginosis.

Bacterial vaginosis is characterized by replacement of the normal Lactobacillus-predominant vaginal flora with Gardnerella vaginalis, anaerobic bacteria, and Mycoplasma hominis. The present study evaluated the vaginal flora of women with bacterial vaginosis before and after treatment with intravaginal clindamycin cream. Sixty-seven nonpregnant women with symptoms and signs of bacterial vaginosis, and without other genital tract infections, were randomly assigned to receive placebo cream or 0.1, 1, or 2% clindamycin cream. Quantitative vaginal cultures for facultative and anaerobic bacteria and genital mycoplasmas were performed at enrollment and at 4-7 days and 4-5 weeks after completion of therapy. At enrollment, G vaginalis was recovered from 99%, Bacteroides sp from 94%, Peptostreptococcus sp from 81%, and M hominis from 58% of the 67 women with bacterial vaginosis. The vaginal cultures yielded a median of 12 isolates per specimen, with equal numbers of aerobic and anaerobic species. The mean log concentration was 1.2 X 10(9) cfu/mL for aerobic and 2.6 X 10(8) cfu/mL for anaerobic bacteria. After treatment, the frequency and concentration of bacteria per milliliter of vaginal fluid decreased for G vaginalis, Bacteroides sp, Peptostreptococcus sp, and M hominis. The 2% clindamycin cream had the greatest effect on the bacterial vaginosis-associated flora and resulted in clinical resolution of bacterial vaginosis in 15 (94%) of 16 women. Treatment with lower concentrations of clindamycin cream had less effect on the vaginal flora and resulted in clinical cure in 25 (71%) of 35 women. Therapy was associated with an increase in the frequency and concentration of Lactobacillus, and a probably transient increase in the frequency of Escherichia coli and Enterococcus.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intravaginal↗

PubMed1989

Comparison of methods for diagnosing bacterial vaginosis among pregnant women.

The diagnosis of bacterial vaginosis is usually based on clinical criteria including homogeneous vaginal discharge, an elevated vaginal pH, the presence of clue cells, and an amine odor. We have evaluated the vaginal flora and clinical signs for 593 pregnant women. Gardnerella vaginalis, Bacteroides spp., and Mycoplasma hominis were isolated more frequently among women with clinical signs than among those without clinical signs of bacterial vaginosis in multivariable analyses that controlled for other bacteria. To determine the laboratory method that best predicted bacterial vaginosis, we calculated the sensitivity, specificity, and predictive value of positive and negative tests for Gram-stained vaginal smears, gas-liquid chromatography of vaginal fluid, and G. vaginalis cultures compared with clinical signs. G. vaginalis culture was sensitive (92%) and both gas-liquid chromatography (78%) and Gram-stained vaginal smears (62%) were moderately sensitive in identifying women with three of the four clinical signs of bacterial vaginosis. However, the Gram-stained vaginal smear (95%) was more specific than G. vaginalis culture (69%) or gas-liquid chromatography (81%). The predictive value of a positive test was also higher for the Gram staining (76%) than for G. vaginalis culture (41%) or gas-liquid chromatography (48%).

Adolescent↗

PubMed1988

Relationships of vaginal Lactobacillus species, cervical Chlamydia trachomatis, and bacterial vaginosis to preterm birth.

The frequency of genital infection was compared among women in premature labor who delivered preterm (before 37 weeks), women in preterm labor who delivered at term, and control women who delivered at term. Both groups of women in premature labor were younger and had more previous preterm births than did control women. Women in premature labor who delivered preterm were more likely to experience rupture of membranes, intrapartum fever, and postpartum fever than were control women. The presence of bacterial vaginosis (odds ratio 2.3) and Chlamydia trachomatis (odds ratio 3.9) was positively associated, and Lactobacillus sp (odds ratio 0.2) was negatively associated, with birth before 37 weeks, using multivariable analysis to control for confounding variables.

Bacterial Infections↗

PubMed1979

Comparison of photographic techniques and films used in stereophotogrammetry of the optic disk.

We compared photogrammetric measurements of optic cup volume, area, and depth made from two types of stereophotography and two types of film to determine their effect on the precision of the measurements. We found that measurements from simultaneous stereophotography (Donaldson stereoscopic fundus camera) had a smaller range of values and a smaller mean percent error than measurements from consecutive stereophotography (Zeiss Fundus Flash II camera). However, a Student's t-test for related measures showed no significant difference. The measurements from Kodachrome 25 film and Kodak Photomicrography film varied in range and mean percent error without a pattern. The Student's t-test for related measures showed no significant difference.

Evaluation Studies as Topic↗

PubMed1979

Photogrammetry of the optic disc in glaucoma and ocular hypertension with simultaneous stereo photography.

Stereophotogrammetric evaluations of the optic cup were performed for normal, ocular hypertensive, and glaucomatous eyes. Average volume, area, and depth measurements were progressively larger from normal to ocular hypertensive to glaucomatous eyes, although the distributions of individual values exhibited considerable overlap among the three groups. Similar results were obtained for volume, area, and depth asymmetry between each pair of eyes. None of these measurements was able to distinguish accurately between normal and glaucomatous optic cups. However, normal eyes showed a high correlation (r = +0.85) between area and depth of the optic cup, whereas this area/depth relationship was reduced in ocular hypertensives (r = +0.63) and completely broke down for glaucomatous eyes (r = +0.04). Approximately 89% of the glaucomatous eyes and 47% of the ocular hypertensive eyes were beyond the range of normal area/depth correlation values. These findings represent an improvement over most previous attempts to quantitatively differentiate between normal and glaucomatous eyes on the basis of optic disc measurements alone, and support the hypothesis that optic disc damage usually precedes visual field loss in glaucoma. With further technical refinements such as computer image processing, stereophotogrammetry of the optic cup may become a valuable differential diagnostic technique for glaucoma.

Glaucoma↗

PubMed1978

The limitations of kinetic perimetry in early scotoma detection.

When tested by Goldmann kinetic perimetry ten patients with glaucomatous optic disc cupping had no visual field defects, but visual field defects were detected when tested by threshold static perimetry on the Tubingen perimeter. To improve the detection ability of kinetic perimetry, we suggest placing the interisopter spot-checks close together or expanding the central 30 degrees plotting area.

Evaluation Studies as Topic↗

PubMedDate not supplied

Automated perimetry: background, instruments and methods.

The goal of automated perimetry is to reduce perimetrist involvement and testing time while maintaining standardized test conditions. Proper calibration of the perimeter background luminance and target intensity is important so that results can be compared between examinations and machines. Three testing procedures may be used alone or in combination: kinetic, threshold static and suprathreshold static perimetry. The Octopus and the Perimetron are fully automated perimeters. The former uses threshold static perimetry while the latter uses kinetic and suprathreshold static perimetry. They are operated by small-sized microprocessors using miniature silicone chip circuitry. They are accurately calibrated, fulfilling the specifications deemed necessary by visual psychophysicists. Although data display and plotting problems still exist, automated perimetry is ready for thorough comparisons with Goldmann and Tübinger manual perimetry.

Computers↗