Serratia Chorioamnionitis and Culture Proven Sepsis in a Preterm Neonate: A Case Report and Review of the Literature.

BACKGROUND: Serratia marcescens is a well-known cause of nosocomial infectious outbreaks in the neonatal intensive care unit, with a high mortality rate in the vulnerable preterm population. However, it is not typically associated with neonatal sepsis secondary to intrapartum vertical transmission. We present the case of a preterm male born at 25 weeks and 4 days of gestation in Okinawa, Japan with culture-proven S. marcescens chorioamnionitis and sepsis, as well as a review of the previously published literature. METHODS: We conducted a literature search utilizing MeSH indexing with the headings [chorioamnionitis], [Serratia], and [infant, newborn] limited to "humans" with a publication date range between 1950 and 2020. RESULTS: All reported cases of preterm S. marcescens chorioamnionitis occurred in coastal locations. The majority of cases resulted in spontaneous abortion, and we found no published reports of confirmed S. marcescens chorioamnionitis in conjunction with viable preterm delivery and positive neonatal cultures. In the case presented herein, S. marcescens chorioamnionitis with associated neonatal sepsis was confirmed by positive placental and blood cultures. Bacterial clearance was achieved following an antibiotic course consisting of 5 days of gentamicin and 14 days of meropenem therapy. CONCLUSIONS: S. marcescens is an uncommon cause of chorioamnionitis that can have devastating neonatal consequences, especially in the at-risk preterm population.

Total synthesis of epothilones B and D: stannane equivalents for beta-keto ester dianions.

Studies leading to a total synthesis of epothilones B and D are described. The overall synthetic plan was based on late-stage fragment assembly of two segments representing C(1)-C(9) and C(10)-C(21) of the structure. The C(1)-C(9) fragment was prepared by elaboration of commercially available (2R)-3-hydroxy-2-methylpropanoate at both ends of the three-carbon unit. Introduction of carbons 1-4 containing the gem-dimethyl unit was achieved in a convergent manner using a diastereoselective addition of a stannane equivalent of a beta-keto ester dianion. An enantioselective addition of such a stannane equivalent for a beta-keto ester dianion was also used to fashion one version of the C(10)-C(21) subunit; however, the fragment assembly (using bimolecular esterification followed by ring-closing metathesis) with this subunit failed. Therefore, fragment assembly was achieved using a Wittig reaction; this was followed by macrolactonization to close the macrocycle. The C(10)-C(21) subunit needed for this approach was prepared in an efficient manner using the Corey-Kim reaction as a key element. Other key reactions in the synthesis include a stereoselective SmI(2) reduction of a beta-hydroxy ketone and a critical opening of a valerolactone with aniline which required extensive investigation.