Perinatal Mortality Associated with Positive Postmortem Cultures for Common Oral Flora.

Introduction. To investigate whether maternal oral flora might be involved in intrauterine infection and subsequent stillbirth or neonatal death and could therefore be detected in fetal and neonatal postmortem bacterial cultures. Methods. This retrospective study of postmortem examinations from 1/1/2000 to 12/31/2010 was searched for bacterial cultures positive for common oral flora from heart blood or lung tissue. Maternal age, gestational age, age at neonatal death, and placental and fetal/neonatal histopathological findings were collected. Results. During the study period 1197 postmortem examinations (861 stillbirths and 336 neonatal deaths) were performed in our hospital with gestational ages ranging from 13 to 40+ weeks. Cultures positive for oral flora were identified in 24 autopsies including 20 pure and 8 mixed growths (26/227, 11.5%), found in 16 stillbirths and 8 neonates. Microscopic examinations of these 16 stillbirths revealed 8 with features of infection and inflammation in fetus and placenta. The 7 neonatal deaths within 72 hours after birth grew 6 pure isolates and 1 mixed, and 6 correlated with fetal and placental inflammation. Conclusions. Pure isolates of oral flora with histological evidence of inflammation/infection in the placenta and fetus or infant suggest a strong association between maternal periodontal conditions and perinatal death.

Identification of bacteria in paraffin-embedded tissues using 16S rDNA sequencing from a neonate with necrotizing enterocolitis.

The conventional approach to bacterial identification in paraffin-embedded tissue relies mainly on morphology, with the aid of Gram stain. This approach is only able to provide some clues; it does not offer the capability of accurate identification. Bacterial identification based on sequencing of 16S ribosomal DNA (rDNA) is able to identify bacteria to the species level. Here we demonstrate the application of this technique in the postmortem examination, for which we had obtained different results from premortem and postmortem blood cultures. In the postmortem examination, abundant gram-negative rods were present in gastrointestinal tract lumen and lymphatic space. DNA was extracted from paraffin-embedded tissue of the above sections and subjected to 16S rDNA polymerase chain reaction for the first 500 base pairs, followed by sequencing. The results of sequencing correlated well with the postmortem culture result. In this review, the newly emerging field of bacterial identification with molecular techniques employing both broad-range and targeted approaches and their clinical applications and limitations are discussed.

Evaluation of a new selective enrichment broth for detection of group B streptococci in pregnant women.

Studies at two Brown Medical School-affiliated hospitals were undertaken to evaluate a new selective broth medium (GBS broth) and to compare it to the LIM broth currently used to culture for group B streptococci. Beta-hemolytic group B streptococci produce a carotenoid pigment that turns GBS broth an orange color. From a total of 580 pregnant women, duplicate vaginal-rectal swabs were collected at 35 to 37 weeks of gestation and cultured for group B streptococci, using either LIM broth (a selective broth containing antibiotics) or GBS broth for enrichment. Specimens were either transported to the laboratory or immediately placed in the respective enrichment broths and delivered to the laboratory. GBS broth medium had sensitivity, specificity, and positive and negative predictive values of 87.8, 100, 100, and 95.1% when planted in the laboratory and 90.3, 100, 100 and 97.6%, respectively, when inoculated at bedside. Use of GBS broth would satisfy Centers for Disease Control and Prevention requirements and would provide faster, more-sensitive, and cost-effective detection of group B streptococci in pregnant women.