George R. Evaldson

Premature rupture of the membranes and ascending infection

Summary. The association of premature rupture of the membranes (PROM) and ascending infection was investigated in 15 women. Bacteriological, histological and immunofluorescence methods were used to study infection at various levels in the birth canal. In most of the women the membranes as well as the placentae showed heavy bacterial invasion. Bacterial distribution within the membranes showed a choriodecidual preponderance. Ascending infection appears to follow the choriodecidual route and may be a primary pathogenetic event in many instances of PROM. The anaerobe Bacteroides fragilis, which is very infrequently isolated in normal pregnant women, was found in five out of 15 women. Two infants had congenital pneumonia caused by group B streptococci and Haemophilus influenzae respectively. The neonatal outcome with PROM may be influenced by the efficiency of the individual defence mechanisms including the antimicrobial capacity of amniotic fluid.

Microbiological findings in pregnant women with premature rupture of the membranes

From 30 consecutive cases of premature rupture of the membranes (PROM) and matched controls, specimens from urine, cervix, amniotic fluid, and placenta as well as neonatal nose and throat swabs were investigated bacteriologically and virologically. In addition virus serological investigation was done. Among the PROM cases the anaerobic cervical isolates outnumbered the aerobic ones, and the total number of aerobic as well as anaerobic isolates was less in the control group. The anaerobesB. fragilis andStrept. intermedius were isolated from the cervix, amniotic fluid, or placenta in 23% and 30% of the PROM patients, respectively. None of the controls harbouredB. fragilis, whileStrept. intermedius was isolated from 6.7% of the controls. Group B streptococci were recovered from the mothers cervix in 20% of the PROM patients and in 6.7% among the controls. Four cases of neonatal septicaemia were encountered, and another two cases were clinically suspected, but not microbiologically verified, contributing to a high perinatal mortality rate (17,6%). Of the PROM patients, 27% developed puerperal infection, while none of the control mothers had such complications. The significance of the anaerobic bacteria as well as group B streptococci for the maternal and neonatal outcome in cases of PROM is discussed, and a possible aetiological role of ascending infection in this complication of pregnancy is postulated.

Bacteroides fragilis, Streptococcus intermedius and Group B Streptococci in Ascending Infection of Pregnancy

By means of bacteriological, histological and immunofluorescence methods, the ascending spread of endocervically inoculated bacteria was studied in 14 pregnant sheep. 8 ewes near term were exposed to group B streptococci, Bacteroides fragilis or Streptococcus intermedius for 2-4 days. 6 other animals in mid pregnancy were exposed to one of the bacteria mentioned for 30 days. Before inoculation, aerobic and anaerobic culture specimens from cervix and amniotic fluid were obtained. At delivery by caesarean section, in addition to culture specimens, membrane and placental tissues were collected. Bacterial detection by means of indirect immunofluorescence showed significant invasion of the membranes and the placentas by the microorganisms inoculated. In one case, inoculated with S. intermedius, the ascending infection could be shown to pass the intact membranes reaching the amniotic fluid. It is concluded that endocervical bacteria in the indigenous microflora might cause pregnancy complications by establishing ascending infection. Furthermore, as the bacteria tested have been implicated in premature rupture of the membranes, an aetiological role of ascending infection in this pregnancy complication is postulated.

Is the Collagen Content Reduced when the Fetal Membranes Rupture

In 15 patients experiencing premature rupture of the fetal membranes (PROM) and in 15 control subjects having delivered spontaneously at term, the collagen content of the membranes was determined by the hydroxyproline method. From each patient two membrane specimens were obtained, one from the rupture margin and another from the membranes in close relation to the placental margin. No significant difference in the collagen content was demonstrated between the two groups of patients. Moreover, no significant difference was observed comparing the collagen content within the paired membrane specimens of each patient in each group. Neither was there any obvious change in the membrane collagen content in relation to clinical signs of chorioamnionitis or microbiological findings. It is concluded that changes in the collagen content of the fetal membranes bear no significance as to the etiology of PROM, neither is such a change involved in the mechanism of membrane rupture at term.

Does the Hygroscopic Property of the Laminaria Tent Imply a Risk for Ascending Infection in Legal Abortions?: A microbiological study

In 53 women admitted for first‐trimester abortion, the cervical canal was dilated with laminaria tents prior to vacuum aspiration. Before insertion of the tents, endocervical specimens were taken for microbiological investigations, including Chlamydia trachomatis, and both aerobic and anaerobic microorganisms. The laminaria tents, widened by their hygroscopic properties, were removed just before the vacuum aspiration and sent for cultivation of aerobic and anaerobic microorganisms. The Grampositive aerobic cocci, Staph. epidermidis, Strept. faecalis and Strept. agalactiae as well as Escherichia coli and Klebsiella/Enterobacter were the most frequent microorganism among the aerobic isolates from the endocervices as well as from the laminaria tents. These microorganisms were identified on the tents in greater numbers than in the cervices. Staph. aureus was isolated from three laminaria tents, but only one of these 3 women was proved to be primarily colonized endocervically. Among the anaerobes, Bacteroidaceae followed by peptococci and peptostreptococci were the predominant genera found in the cervix as well as on the removed laminaria tents. These three groups of anaerobic microorganisms were found markedly less frequently on the laminaria tents than in the endocervix. On the other hand, Strept. intermedius, another anaerobe of possible enteric origin, was recovered from 9 laminaria tents but not in the cervices. Since no cases of clinically verified endometritis/salpingitis were registered in the present study it is concluded that the risk of a pelvic inflammatory disease (PID) due to the laminaria tent is negligible as long as the laminaria treatment does not exceed 24 hours.

Single-dose intravenous tinidazole prophylaxis in abdominal hysterectomy

In 100 patients undergoing abdominal hysterectomy, a double‐blind study was undertaken to evaluate the efficacy of prophylactic tinidazole treatment in diminishing the postoperative infection rate. the patients treated received a single dose of 1 600 mg tinidazole i.v. during 2 h preoperatively. One patient each from the placebo and treatment groups was excluded since the operations was ultimately not hysterectomy. the two groups of women, 49 in each, were comparable with regard to age, previous obstetrical and gynecological history, and reason for hysterectomy. Significant infectious complications (pelvic cellulitis, vaginal cuff abscess, pelvic abscess) were observed in 9 (18.4%) of the 49 placebo patients, but in only 3 (6.1%) of the 49 tinidazole‐treated patients. Mild or mode rate wound infections were found in 2 patients of each group (4%). Urinary tract infections were found in 10 placebo (20.4%) and 12 tinidazole‐treated patients (24.5%). Among patients developing cuff abscesses, Bacteroides was the most frequently isolated anaerobic genus, B. bivius being the predominant species, while bacteria of enteric origin such as Escherichia coli and Streptococcus faecalis were the most common aerobic isolates.

The role of immunoglobulins in amniotic fluid growth inhibition ofBacteroides fragilis, herpes simplex, coxsackie B 5 and cytomegalovirus

In serum and amniotic fluid (AF) from 30 pregnant women, antibodies against the anaerobeBacteroides fragilis were determined by enzyme-linked immunosorbent assay (ELISA) and the results were compared with those of previously performed tests ofB. fragilis growth inhibition by AF. The neutralizing effects of serum and AF against herpes simplex virus (HSV), cytomegalovirus (CMV) and coxsackie B 5 virus were also investigated, and antibody titres were determined by ELISA. No correlation could be demonstrated between the growth-inhibitory capacity of AF and the presence of antibodies againstB. fragilis in serum or AF. Neutralizing antibodies against HSV and coxsackie B 5 virus were found in 73% and 51%, respectively, of the sera and in 36% and 13%, respectively, of both serum and corresponding AF. In no case could an AF neutralizing effect upon HSV, coxsackie B 5 or CMV be demonstrated without a corresponding positive serum neutralization. It is concluded that the growth-inhibitory effect of AF on viruses in antibody-mediated, while AF inhibition ofB. fragilis, and possibly other bacteria as well, seems to depend upon other antimicrobial mechanisms.

Is the Fibrinolytic Activity Involved in the Mechanism of Fetal Membrane Rupture

The fibrinolytic activity (FA) was determined in fetal membrane specimens obtained in 15 cases of premature rupture of the membranes (PROM) and from 15 control women who gave birth spontaneously at term. In each case two membrane specimens were obtained, one from the rupture margin and the other from the membranes close to the placental margin. No significant difference in FA was demonstrated between the two groups of patients. Nor could any significant difference be found on comparing the FA within the paired membrane specimens of each group. Furthermore, no obvious change in FA was demonstrated in relation to clinical signs of chorioamnionitis or microbiological findings. However, although the FAs observed in prematurely ruptured membranes were comparable to those found in term specimens, this does not exclude the possibility of an involvement of FA in the mechanism of membrane rupture.

Does an intracervical infection influence the fibrinolytic activity and the collagen content of the fetal membranes? A study of ascending infections in pregnant ewes

Apart from solely mechanical explanations, premature rupture of the membranes (PROM) has been suggested to be caused by an ascending infection. In order to investigate the role of infection in the mechanism of PROM, pregnant ewes were experimentally inoculated endocervically with either Bacteroides fragilis, Streptococcus intermedius or group B streptococci. These microorganisms were previously reported to be implicated in PROM in humans. The present investigation concerns the possible effect of an experimentally induced ascending infection on the collagen content and fibrinolytic activity (FA) of the fetal membranes. No relationship was observed between an ascending infection during pregnancy and the collagen content content of the fetal membrane specimens. It was concluded that changes in the collagen content bear no etiological significance in the mechanism of premature membrane rupture irrespective of an ascending infections being present or not. Concerning FA in only one case, experiencing a Strept. intermedius amnionitis, was an elevated FA value observed. This finding indicates that the involvement of FA in the process of membrane rupture following ascending infection during pregnancy cannot be ruled out.

Premature Rupture of the Membranes and Ascending Infection

The association of premature rupture of the membranes (PROM) and ascending infection was investigated in 15 women. Bacteriological, histological and immunofluorescence methods were used to study infection at various levels in the birth canal. In most of the women the membranes as well as the placentae showed heavy bacterial invasion. Bacterial distribution within the membranes showed a choriodecidual preponderance. Ascending infection appears to follow the choriodecidual route and may be a primary pathogenetic event in many instances of PROM. The anaerobe Bacteroides fragilis, which is very infrequently isolated in normal pregnant women, was found in five out of 15 women. Two infants had congenital pneumonia caused by group B streptococci and Haemophilus influenzae respectively. The neonatal outcome with PROM may be influenced by the efficiency of the individual defence mechanisms including the antimicrobial capacity of amniotic fluid.