Microbiological findings in pregnant women with premature rupture of the membranes

Vulvovaginal yeast infections during pregnancy and perinatal outcomes: systematic review and meta-analysis

BACKGROUND

Vulvovaginal yeast infections in pregnancy are common and can cause extensive inflammation, which could contribute to adverse pregnancy outcomes. Symptomatic yeast infections are likely to cause more inflammation than asymptomatic. The objective of this study was to investigate associations between symptomatic and asymptomatic vulvovaginal yeast infections in pregnancy and perinatal outcomes.

METHODS

We did a systematic review and searched eight databases until 01 July 2022. We included studies reporting on pregnant women with and without laboratory confirmed vulvovaginal yeast infection and preterm birth or eight other perinatal outcomes. We used random effects meta-analysis to calculate summary odds ratios (OR), 95% confidence intervals (CI) and prediction intervals for the association between yeast infection and outcomes. We described findings from studies with multivariable analyses. We assessed the risk of bias using published tools.

RESULTS

We screened 3909 references and included 57 studies. Only 22/57 studies reported information about participant vulvovaginal symptoms. Preterm birth was an outcome in 35/57 studies (49,161 women). In 32/35 studies with available data, the summary OR from univariable analyses was 1.01 (95% CI 0.84-1.21, I2 60%, prediction interval 0.45-2.23). In analyses stratified by symptom status, we found ORs of 1.44 (95% CI 0.92-2.26) in two studies with ≥ 50% symptomatic participants, 0.84 (95% CI 0.45-1.58) in seven studies with < 50% symptomatic participants, and 1.12 (95% CI 0.94-1.35) in four studies with asymptomatic participants. In three studies with multivariable analysis, adjusted ORs were greater than one but CIs were compatible with there being no association. We did not find associations between vulvovaginal yeast infection and any secondary outcome. Most studies were at high risk of bias in at least one domain and only three studies controlled for confounding.

CONCLUSIONS

We did not find strong statistical evidence of an increased risk for preterm birth or eight other adverse perinatal outcomes, in pregnant women with either symptomatic or asymptomatic vulvovaginal yeast infection. The available evidence is insufficient to make recommendations about testing and treatment of vulvovaginal yeast infection in pregnancy. Future studies should assess vulvovaginal symptoms, yeast organism loads, concomitant vaginal or cervical infections, and microbiota using state-of-the-art diagnostics.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020197564.

Interactions Between Intestinal Microbiota and Neural Mitochondria: A New Perspective on Communicating Pathway From Gut to Brain

Many studies shown that neurological diseases are associated with neural mitochondrial dysfunctions and microbiome composition alterations. Since mitochondria emerged from bacterial ancestors during endosymbiosis, mitochondria, and bacteria had analogous genomic characteristics, similar bioactive compounds and comparable energy metabolism pathways. Therefore, it is necessary to rationalize the interactions of intestinal microbiota with neural mitochondria. Recent studies have identified neural mitochondrial dysfunction as a critical pathogenic factor for the onset and progress of multiple neurological disorders, in which the non-negligible role of altered gut flora composition was increasingly noticed. Here, we proposed a new perspective of intestinal microbiota – neural mitochondria interaction as a communicating channel from gut to brain, which could help to extend the vision of gut-brain axis regulation and provide additional research directions on treatment and prevention of responsive neurological disorders.

Contribution of vaginal culture to predict early onset neonatal infection in preterm prelabor rupture of membranes

BACKGROUND

Preterm prelabor rupture of membranes (PPROM) is a major cause of morbidity and mortality for both the mother and the newborn. The vaginal germ profile in PPROM is poorly known, particularly regarding the risk of early-onset neonatal infection (EONI).

OBJECTIVE

To determine microbiological risk factors for EONI in case of PPROM before 34 weeks of gestation (WG).

STUDY DESIGN

A retrospective single-center cohort of patients with PPROM before 34 W G from 2008 to 2016. Vaginal swabs were obtained at admission and at delivery as per usual care and were analyzed by Gram stain and culture for vaginal dysbiosisi.e lactobacilli depletion and/or presence of potential pathogens.

RESULTS

Among 268 cases of PPROM, 39 neonates had EONI 14.55 %; (95 %CI 0.11 - 0.19) Overall, vaginal samples culture was positive in 16.67 % (95 %CI 11.95 %-22.32 %) at the time of rupture and 24.76 % (95 %CI 19.02 %-31.23 %) at delivery, with no significant differences between EONI and no-EONI groups (p = 0.797 and 0.486, respectively), including for Group B Streptococci (GBS) and Escherichia coli. EONI was significantly associated with dysbiosis at the time of rupture (23.94 % versus 10.35 % in the absence of dysbiosis, p = 0.009) and at delivery (19.70 % versus 3.90 % if no dysbiosis, p < 0.001). Clinical intra-uterine infection was present in 78.5 % (n = 31) of the EONI group versus 37.2 % (n = 85) in the non-EONI group (p < 0.001) and chorioamnionitis and/or funisitis were found in 97.3 % and 91.9 %, respectively in the EONI group, versus 56.11 % and 53.96 %, respectively, in the non-EONI group (p < 0.001).

CONCLUSION

Dysbiosis following rupture and at delivery, but not the presence of pathogens in the VS culture, was associated with the risk of EONI in case of PPROM.

A Case of Dialister pneumosintes Bacteremia-Associated Neck and Mediastinal Abscess

BACKGROUND Dialister pneumosintes is a suspected periodontal pathogen. It can affect different parts of the body either by hematogenous transmission or regional spread. Here, we report a case of 30-year-old previously healthy woman diagnosed with mediastinal and neck abscess caused by this pathogen. CASE REPORT A 30-year-old woman presented with a 1-day history of fever, vomiting, and diarrhea. She was on her last dose of a 2-week course of oral antibiotic for suspected dental abscess. On admission, parenteral broad-spectrum antibiotic was started for sepsis of unknown source. Because of intermittent spike of high temperature despite being on an antibiotic, cross-sectional imaging was performed, which revealed a superior mediastinal abscess with extension in the neck. She was referred to the ENT surgeon for incision and drainage of the collection. However, the procedure was complicated by injury to the right internal jugular vein. Her postoperative period was also convoluted with the development of pulmonary embolism, followed by deep vein thrombosis of the right upper limb. Her pus polymerase chain reaction test detected 16s rRNA gene, suggestive of gram-negative anaerobic bacilli, and anaerobic blood culture grew Dialister pneumosintes. After a prolonged course of illness and antibiotic treatment, she recovered well, and now is back to her normal activities. CONCLUSIONS Potential life-threatening complications may develop from periodontal infection by this microorganism. In patients being treated for sepsis of unknown origin, not responding to antibiotic treatment, and with a history of recent periodontal infection, a deep-seated abscess needs to be considered.

Sputum microbiota as a potential diagnostic marker for multidrug-resistant tuberculosis

The prevalence of drug-resistant Mycobacterium tuberculosis (Mtb) strains makes disease control more complicated, which is the main cause of death in tuberculosis (TB) patients. Early detection and timely standard treatment are the key to current prevention and control of drug-resistant TB. In recent years, despite the continuous advancement in drug-resistant TB diagnostic technology, the needs for clinical rapid and accurate diagnosis are still not fully met. With the development of sequencing technology, the research of human microecology has been intensified. This study aims to use 16 rRNA sequencing technology to detect and analyze upper respiratory flora of TB patients with anti-TB drug sensitivity (DS, n = 55), monoresistance isoniazide (MR-INH, n = 33), monoresistance rifampin (MR-RFP, n = 12), multidrug resistance (MDR, n = 26) and polyresistance (PR, n = 39) in southern China. Potential microbial diagnostic markers for different types of TB drug resistance are searched by screening differential flora, which provides certain guiding significance for drug resistance diagnosis and clinical drug use of TB. The results showed that the pulmonary microenvironment of TB patients was more susceptible to infection by external pathogens, and the infection of different drug-resistant Mtb leads to changes in different flora. Importantly, seven novel microorganisms (Leptotrichia, Granulicatella, Campylobacter, Delfitia, Kingella, Chlamydophila, Bordetella) were identified by 16S rRNA sequencing as diagnostic markers for different drug resistance types of TB. Leptotrichia, Granulicatella, Campylobacter were potential diagnostic marker for TB patients with INH single-resistance. Delftia was a potential diagnostic marker for TB patients with RFP single drug-resistance. Kingella and Chlamydophila can be used as diagnostic markers for TB patients with PR. Bordetella can be used as a potential diagnostic marker for identification of TB patients with MDR.

The Crosstalk between the Gut Microbiota and Mitochondria during Exercise

Many physiological changes occur in response to endurance exercise in order to adapt to the increasing energy needs, mitochondria biogenesis, increased reactive oxygen species (ROS) production and acute inflammatory responses. Mitochondria are organelles within each cell that are crucial for ATP production and are also a major producer of ROS and reactive nitrogen species during intense exercise. Recent evidence shows there is a bidirectional interaction between mitochondria and microbiota. The gut microbiota have been shown to regulate key transcriptional co-activators, transcription factors and enzymes involved in mitochondrial biogenesis such as PGC-1α, SIRT1, and AMPK genes. Furthermore, the gut microbiota and its metabolites, such as short chain fatty acids and secondary bile acids, also contribute to host energy production, ROS modulation and inflammation in the gut by attenuating TNFα- mediated immune responses and inflammasomes such as NLRP3. On the other hand, mitochondria, particularly mitochondrial ROS production, have a crucial role in regulating the gut microbiota via modulating intestinal barrier function and mucosal immune responses. Recently, it has also been shown that genetic variants within the mitochondrial genome, could affect mitochondrial function and therefore the intestinal microbiota composition and activity. Diet is also known to dramatically modulate the composition of the gut microbiota. Therefore, studies targeting the gut microbiota can be useful for managing mitochondrial related ROS production, pro-inflammatory signals and metabolic limits in endurance athletes.

Genital tract microbial isolate in women with preterm pre-labour rupture of membranes in resource-constrained community setting

This study determined patterns of microbial isolates in genital tract of women with preterm pre-labour rupture of membranes (PPROM) compared with cases without PPROM. Endocervical swabs of women with confirmed diagnosis of PPROM were examined microbiologically and compared in blinded pattern with gestational-age-matched controls. One hundred and five microbiological results each for cases and controls were analysed. Positive microbial cultures were seen in 79.05% of cases versus 6.67% of controls. Streptococcus spp. (31.43%) was the commonest organism isolated in cases (p < 0.001), while Candida albicans was significantly more in controls (p < 0.001). The highest incidence of PPROM (82.86%) occurred in gestational ages of 28-30 and 34-36 weeks. No fewer than 75.24% cases occurred in low parity (0-2). Majority occurred in extremes of viable preterm gestation and in women of low parity.

mtDNA haplogroup and single nucleotide polymorphisms structure human microbiome communities

Background

Although our microbial community and genomes (the human microbiome) outnumber our genome by several orders of magnitude, to what extent the human host genetic complement informs the microbiota composition is not clear. The Human Microbiome Project (HMP) Consortium established a unique population-scale framework with which to characterize the relationship of microbial community structure with their human hosts. A wide variety of taxa and metabolic pathways have been shown to be differentially distributed by virtue of race/ethnicity in the HMP. Given that mtDNA haplogroups are the maternally derived ancestral genomic markers and mitochondria’s role as the generator for cellular ATP, characterizing the relationship between human mtDNA genomic variants and microbiome profiles becomes of potential marked biologic and clinical interest.

Results

We leveraged sequencing data from the HMP to investigate the association between microbiome community structures with its own host mtDNA variants. 15 haplogroups and 631 mtDNA nucleotide polymorphisms (mean sequencing depth of 280X on the mitochondria genome) from 89 individuals participating in the HMP were accurately identified. 16S rRNA (V3-V5 region) sequencing generated microbiome taxonomy profiles and whole genome shotgun sequencing generated metabolic profiles from various body sites were treated as traits to conduct association analysis between haplogroups and host clinical metadata through linear regression. The mtSNPs of individuals with European haplogroups were associated with microbiome profiles using PLINK quantitative trait associations with permutation and adjusted for multiple comparisons. We observe that among 139 stool and 59 vaginal posterior fornix samples, several haplogroups show significant association with specific microbiota (q-value < 0.05) as well as their aggregate community structure (Chi-square with Monte Carlo, p < 0.005), which confirmed and expanded previous research on the association of race and ethnicity with microbiome profile. Our results further indicate that mtDNA variations may render different microbiome profiles, possibly through an inflammatory response to different levels of reactive oxygen species activity.

Conclusions

These data provide initial evidence for the association between host ancestral genome with the structure of its microbiome.

Leptotrichia species in human infections

Leptotrichia species typically colonize the oral cavity and genitourinary tract. These anaerobic bacteria belong to the normal flora of humans and are seldom found in clinically significant specimens. However, on rare occasions, Leptotrichia has been isolated from blood cultures of patients with lesions in the oral mucosa, in particular from patients with neutropenia. These organisms should be considered potential pathogens in neutropenic patients, especially when breaks in the mucosal barriers are present through which they frequently spread to the bloodstream. Leptotrichia has also been recovered from immunocompetent persons, e.g. patients with endocarditis. Although their role in infections remains elusive and not much is known, they have been suggested as emerging pathogens. The present review deals with taxonomy, diagnosis, clinical importance, pathogenesis, host defence, infection control, and spectrum of Leptotrichia infections, and ends with a few typical case reports. Currently, six species have been validly published, but a number of yet uncultivable species exist. Molecular methods recovering uncultivable species should be used to get a real idea of their role as pathogens.

Antimicrobial susceptibilities and clinical sources of Dialister species

Seventy-four strains representing the four species of the genus Dialister were isolated from various clinical samples. Dialister pneumosintes and Dialister micraerophilus were the two mainly encountered species. Fifty-five isolates were tested against 14 antimicrobial agents. Decreased susceptibilities to piperacillin, metronidazole, macrolides, fluoroquinolones, and rifampin were demonstrated. The clinical impact of these decreased susceptibilities remains to be investigated but should prompt microbiologists to perform antimicrobial susceptibility testing for clinically important Dialister spp.

Leptotrichia amnionii, an emerging pathogen of the female urogenital tract

Leptotrichia amnionii, a recently described, very fastidious, gram-negative anaerobic bacterium, is an opportunistic pathogen of the female urogenital tract. We report a case of second-trimester abortion in a patient with chorioamnionitis and L. amnionii bacteremia and a case of renal abscess in a female 5 weeks postpartum.

Isolation of Dialister pneumosintes isolated from a bacteremia of vaginal origin

In this report, we review one case of bacteremia infection due to Dialister pneumosintes. The patient was admitted in post-partum with vaginosis and suppurative thrombosis of the ovarian veina. D. pneumosintes was isolated in pure culture from the three blood culture flasks. Identification of this bacterium was difficult and requires the amplification and partial sequencing of the 16S rRNA gene. The patients had favorable outcome after antibiotic treatment.

Peripartum bacteremias due to Leptotrichia amnionii and Sneathia sanguinegens, rare causes of fever during and after delivery

We report three cases of delivery and postpartum bacteremia due to unusual anaerobic bacteria in healthy young women. Leptotrichia amnionii bacteremia occurred during delivery in two mothers and was associated with fetal distress during labor. Conversely, Sneathia sanguinegens bacteremia occurred postpartum, 2 days after delivery, without consequence for the neonate.

Childhood asthma hospitalization risk after cesarean delivery in former term and premature infants

BACKGROUND

Cesarean delivery modifies infant gut bacterial flora composition, which may result in hindered tolerance to allergenic substances, thereby increasing the risk of asthma in accordance with the hygiene hypothesis. Results of previous studies regarding an association between birth route and asthma are conflicting, and these studies have not evaluated some potential confounding effects, including prematurity and maternal asthma.

OBJECTIVE

To determine whether cesarean delivery in full-term and premature infants increases the risk of subsequent childhood asthma hospitalization.

METHODS

We conducted a case-control study using the Washington State Birth Events Record Database linked to statewide hospitalization data. The study included 2,028 children hospitalized for asthma (cases) and 8,292 age-matched controls.

RESULTS

Cesarean delivery was modestly associated with an increased risk of asthma hospitalization (odds ratio [OR], 1.20; 95% confidence interval [CI], 1.04-1.39). However, when analyzed separately, there was an association between cesarean delivery and asthma hospitalization in premature infants (OR, 1.90; 95% CI, 1.09-3.02) but not in full-term infants (OR, 1.15; 95% CI, 0.97-1.34).

CONCLUSIONS

Cesarean delivery was associated with subsequent asthma hospitalization only in premature infants. Because mothers with asthma are reported to have increased rates of cesarean delivery and premature delivery, other factors in addition to the hygiene hypothesis, including genetic and in utero influences associated with maternal asthma, may contribute to the increased risk of asthma in premature infants.

Genetic diversity of Leptotrichia and description of Leptotrichia goodfellowii sp. nov., Leptotrichia hofstadii sp. nov., Leptotrichia shahii sp. nov. and Leptotrichia wadei sp. nov

Sixty strains of Gram-negative, anaerobic, rod-shaped bacteria from human sources initially assigned to Leptotrichia buccalis (n=58) and 'Leptotrichia pseudobuccalis' (n=2) have been subjected to polyphasic taxonomy. Full-length 16S rDNA sequencing, DNA-DNA hybridization, RAPD, SDS-PAGE of whole-cell proteins, cellular fatty acid analysis and enzymic/biochemical tests supported the establishment of four novel Leptotrichia species from this collection, Leptotrichia goodfellowii sp. nov. (type strain LB 57(T)=CCUG 32286(T)=CIP 107915(T)), Leptotrichia hofstadii sp. nov. (type strain LB 23(T)=CCUG 47504(T)=CIP 107917(T)), Leptotrichia shahii sp. nov. (type strain LB 37(T)=CCUG 47503(T)=CIP 107916(T)) and Leptotrichia wadei sp. nov. (type strain LB 16(T)=CCUG 47505(T)=CIP 107918(T)). Light and electron microscopy showed that the four novel species were Gram-negative, non-spore-forming and non-motile rods. L. goodfellowii produced arginine dihydrolase, beta-galactosidase, N-acetyl-beta-glucosaminidase, arginine arylamidase, leucine arylamidase and histidine arylamidase. L. shahii produced alpha-arabinosidase. L. buccalis and L. goodfellowii fermented mannose and were beta-galactosidase-6-phosphate positive. L. goodfellowii, L. hofstadii and L. wadei were beta-haemolytic. L. buccalis fermented raffinose. With L. buccalis, L. goodfellowii showed 3.8-5.5 % DNA-DNA relatedness, L. shahii showed 24.5-34.1 % relatedness, L. hofstadii showed 27.3-36.3 % relatedness and L. wadei showed 24.1-35.9 % relatedness. 16S rDNA sequencing demonstrated that L. hofstadii, L. shahii, L. wadei and L. goodfellowii each formed individual clusters with 97, 96, 94 and 92 % similarity, respectively, to L. buccalis.

Dialister pneumosintes associated with human brain abscesses

In this report, we review two cases of brain infection due to Dialister pneumosintes in previously healthy patients. The bacterium was isolated from the first patient by blood culture and directly from a brain abscess in the second patient. In both cases, the infection was suspected to be of nasopharyngeal or dental origin. The patients had favorable outcomes following surgical debridement and antibiotic treatment. After in vitro amplification and partial sequencing of the 16S rRNA gene, two strains were classified as D. pneumosintes. However, traditional biochemical tests were not sufficient to identify the bacteria. In addition to causing periodontal and opportunistic infections, D. pneumosintes, contained in mixed flora, may behave as a clinically important pathogen, especially in the brain. In addition to phenotypic characterization, 16S rRNA partial sequencing was used to identify D. pneumosintes definitively.

Study of β-Lactam antibiotic susceptibilites and characteristics of penicillin-binding proteins from Streptococcus anginosus, S. constellatus and S. intermedius

Twenty-two isolates from dentoalveolar abscesses from 11 patients belonging to the Streptococcus milleri group were classified into 3 species, S. anginosus, S. constellatus and S. intermedius, according to their patterns of glycosidase production. The minimum inhibitory concentration (MIC) values of 6 β-lactams, penicillin G (PCG), ampicillin (ABPC), cefaclor (CCL), cephalexin (CEX), flomoxef (FMOX) and imipenem (IPM), were all within a narrow range against the 3 species and were close to those of the corresponding type strains. All of the isolates were more susceptible to PCG, ABPC and IPM than to CCL and CEX. Highly β-lactam-resistant strains were not observed. Fluorogram patterns of penicillin-binding proteins (PBPs) were similar within the S. milleri group. Some isolates of S. anginosus and S. constellatus had extra bands which were not detected in the type strains, so that the PBP band patterns may not be able to accurately identify the species within the S. milleri group, especially between S. anginosus and S. constellatus. These results support the view that a genetically close relationship exists among the different species within this group. ABPC showed stronger affinities for almost all PBPs compared with CCL, reflected by lower ABPC MIC values. The PBPs with the highest affinity for ABPC were different from those for CCL. However, scanning electron microscopic observations showed that morphological changes of the bacterial cells were similar after treatment with these antibiotics at their MICs.

Premature rupture of membranes and bacterial vaginosis

OBJECTIVE

Critically review obstetric, epidemiologic, microbiologic, and pathophysiologic information regarding the possible casual associations of bacterial vaginosis with premature rupture of membranes.

METHODS

Observational and experimental studies are reviewed and correlated with in vitro and clinical, microbiologic, and pathophysiologic experiments in an effort to define possibly casual relationships with bacterial vaginosis and premature rupture of membranes and its maternal and perinatal sequelae.

RESULTS

Considerable information shows that bacterial vaginosis, a common vaginal microbe-associated condition of reproductive age women, can be strongly (risk ratios up to 7.3, confidence interval 95%, 1.8 to 29.4) associated with preterm premature rupture of membranes as well as preterm labor and birth. Microorganisms of bacterial vaginosis produce factors including proteases (IgAse, collagenase, etc.) that can facilitate transport of bacteria to fetal membranes and impair fetal membrane integrity in experimental models.

CONCLUSIONS

Controlled investigations are required to evaluate if treatment of bacterial vaginosis is associated with reduction of premature rupture of membranes and preterm birth.

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 infection's 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.

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 Gram-positive 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.

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

In serum and amniotic fluid (AF) from 30 pregnant women, antibodies against the anaerobe Bacteroides fragilis were determined by enzyme-linked immunosorbent assay (ELISA) and the results were compared with those of previously performed tests of B. 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 against B. 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 B5 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 of B. fragilis, and possibly other bacteria as well, seems to depend upon other antimicrobial mechanisms.

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.

Amniotic fluid activity against Bacteroides fragilis and group B streptococci

The antimicrobial capacity of amniotic fluid (AF) against B. fragilis, group B streptococci and Escherichia coli, the latter as a reference indicator, was investigated in samples from 30 patients. In order to study trimester as well as individual variations in the antibacterial activity, 10 individual samples from each trimester of pregnancy (AF1, AF2, AF3), were separately tested. With B. fragilis all trimester samples showed initial inhibition lasting for 8 h, the bacteria then regaining growth capacity in all AF1, and the majority of AF2 and AF3 specimens. However, 4 AF2 and 3 AF3 samples showed continued bacteriostatic activity for up to 24 h. Group B streptococci exhibited uninhibited growth in all trimester samples. The growth of E. coli in AF1 and AF2 was not inhibited, whereas in AF3 a temporary arrest was observed at 8 h, this being followed by growth to control levels at 24 h. The findings may explain the frequent isolation of B. fragilis from cases of septic abortions during the first trimester. Individual variation in the effectiveness of the antibacterial activity against B. fragilis in AF2 and AF3 may explain why this microorganism, which is often implicated in severe maternal and neonatal infections, is occasionally recovered from the mother's endocervix without signs of disease. The inefficacy of AF in defence against group B streptococci correlates well with the frequent isolation of these bacteria from cases of severe congenital infections associated with premature delivery.