A phage tail-like bacteriocin suppresses competitors in metapopulations of pathogenic bacteria.

Bacteria can repurpose their own bacteriophage viruses (phage) to kill competing bacteria. Phage-derived elements are frequently strain specific in their killing activity, although there is limited evidence that this specificity drives bacterial population dynamics. Here, we identified intact phage and their derived elements in a metapopulation of wild plant-associated Pseudomonas genomes. We discovered that the most abundant viral cluster encodes a phage remnant resembling a phage tail called a tailocin, which bacteria have co-opted to kill bacterial competitors. Each pathogenic Pseudomonas strain carries one of a few distinct tailocin variants that target the variable polysaccharides in the outer membrane of co-occurring pathogenic Pseudomonas strains. Analysis of herbarium samples from the past 170 years revealed that the same tailocin and bacterial receptor variants have persisted in Pseudomonas populations. These results suggest that tailocin genetic diversity can be mined to develop targeted "tailocin cocktails" for microbial control.

A weaponized phage suppresses competitors in historical and modern metapopulations of pathogenic bacteria.

Bacteriophages, the viruses of bacteria, are proposed to drive bacterial population dynamics, yet direct evidence of their impact on natural populations is limited. Here we identified viral sequences in a metapopulation of wild plant-associated Pseudomonas spp. genomes. We discovered that the most abundant viral cluster does not encode an intact phage but instead encodes a tailocin - a phage-derived element that bacteria use to kill competitors for interbacterial warfare. Each pathogenic Pseudomonas sp. strain carries one of a few distinct tailocin variants, which target variable polysaccharides in the outer membrane of co-occurring pathogenic strains. Analysis of historic herbarium samples from the last 170 years revealed that the same tailocin and receptor variants have persisted in the Pseudomonas populations for at least two centuries, suggesting the continued use of a defined set of tailocin haplotypes and receptors. These results indicate that tailocin genetic diversity can be mined to develop targeted "tailocin cocktails" for microbial control. One-Sentence Summary: Bacterial pathogens in a host-associated metapopulation use a repurposed prophage to kill their competitors.

Duration of the Third Stage of Labor and Estimated Blood Loss in Twin Vaginal Deliveries.

Objective The main aim of this study was to characterize the duration of the third stage of labor and estimated blood loss in twin vaginal deliveries. Study Design This was a retrospective case-control study. The data was collected from deliveries at the University of Arkansas for Medical Sciences in Little Rock, Arkansas, from January 2013 to June 2017. Women were identified who had twin gestation, were delivered vaginally, and whose maternal age was greater than 18 years old. Women were excluded if they had an intrauterine fetal demise, delivered either/both fetuses via cesarean, history of a previous cesarean or a fetus with a congenital anomaly. If a subject met criteria to be included in the study, the next normal singleton vaginal delivery was used as the control subject. Results There were 132 singleton vaginal deliveries and 133 twin vaginal deliveries analyzed. There was no significant difference in the length of the third stage of labor between twin and singleton vaginal deliveries except in the 95th percentile of the distribution. Mothers delivering twins had an increase in third-stage duration by 7.618 minutes (95% confidence interval [CI]: 0.73, 14.50; p = 0.03) compared with those who delivered singletons. The twin group had a higher estimated blood loss than singleton deliveries. The increase in blood loss in the twin group was 149.02 mL (95% CI: 100.2, 197.8), 257.01 mL (95% CI: 117.9, 396.1), and 381.53 mL (95% CI: 201.1, 562.1) at the 50th, 90th, and 95th percentiles, respectively. When the third stage of labor was at the 90th percentile or less in twin pregnancy (14 minutes), estimated blood loss was less than 1000 mL. Conclusion Twin pregnancy is a known risk factor for postpartum hemorrhage. As the duration of the third stage prolongs, the risk for hemorrhage also increases. We recommend delivery of the placenta in twin pregnancies by 15 minutes to reduce this risk. Key Points The third stage is longer in twin pregnancy at extremes.Twin placentas should be delivered by 15 minutes.Manually extract the placenta when third stage is prolonged.

Umbilical Cord Prolapse: A Review of the Literature.

IMPORTANCE: Umbilical cord prolapse is a rare occurrence and is a life-threatening emergency for the fetus. These events are unpredictable and unpreventable. Umbilical cord prolapse requires swift diagnosis and management for optimal outcome. OBJECTIVE: The aim of this review is to describe the incidence, risk factor, pathophysiology, diagnosis, and management of this rare but potentially life-threatening event. EVIDENCE ACQUISITION: A PubMed, Web of Science, and CINAHL search was undertaken with no limitations on the number of years searched. RESULTS: There were 200 articles identified, with 53 being the basis of review. Multiple risk factors for a umbilical cord prolapse have been suggested including fetal malpresentation or abnormal lie, prematurity, multifetal gestation, and polyhydramnios. The diagnosis is largely made by examination and found after rupture of membranes, and most often, examination is prompted by fetal heart rate decelerations. The management of umbilical cord prolapse is expedited delivery; however, there are rare specific scenarios in which immediate delivery is not possible and efforts should be made to relieve cord compression. CONCLUSIONS: Rapid identification of an umbilical cord prolapse facilitates management and increases likelihood of an optimal outcome. The management is an expedited delivery with efforts to relieve cord compression until delivery can be achieved. RELEVANCE: Umbilical cord prolapse is a rare but a life-threatening obstetrical emergency.

Signet Ring Cell Carcinoma with Lymphangitic Carcinomatosis in Pregnancy: A Case Report of an Unexpected Maternal Death and Review of the Literature.

BACKGROUND Cancer in pregnancy is extremely rare, and gastric cancers are rarer still. Diagnosis is difficult in pregnancy due to overlapping symptoms with pregnancy such as nausea, pain, anemia, and fatigue. CASE REPORT A 26-year-old G1 woman at 32 weeks gestation with a past medical history of systemic lupus erythematosus presented with new-onset chest pain and shortness of breath. Computed tomography of the chest, electrocardiogram, and echocardiogram were normal. Laboratory evaluation revealed thrombocytopenia, proteinuria of 480 milligrams, and normal complement. She delivered on hospital day 3 due to worsening chest pain. During cesarean delivery, the patient became hypotensive and hypoxic and required intensive care unit admission after a cesarean hysterectomy. On postoperative day 2 she had a pulmonary embolus and was started on therapeutic anticoagulation. She clinically improved until postoperative day 4, when she was found unresponsive with pulseless electrical activity. After 38 minutes of Advanced Cardiac Life Support, death was pronounced. An autopsy was performed and the cause of death found to be complications of multi-organ system involvement of adenocarcinoma with signet ring cell features. Lymphangitic carcinomatosis was noted throughout the lungs. CONCLUSIONS This patient had adenocarcinoma with signet ring cell features and associated lymphangitic carcinomatosis, which led to her postpartum death. Lymphangitic carcinomatosis is associated with an exceedingly poor prognosis, especially in pregnancy.