Host cell invasion is a major feature of Staphylococcus aureus and contributes to infection development. The intracellular metabolically active bacteria can induce host cell activation and death but they can also persist for long time periods. In this study a comparative analysis was performed of different well-characterized S. aureus strains in their interaction with a variety of host cell types. Staphylococcus aureus (strains 6850, USA300, LS1, SH1000, Cowan1) invasion was compared in different human cell types (epithelial and endothelial cells, keratinocytes, fibroblasts, osteoblasts). The number of intracellular bacteria was determined, cell inflammation was investigated, as well as cell death and phagosomal escape of bacteria. To explain strain-dependent differences in the secretome, a proteomic approach was used. Barrier cells took up high amounts of bacteria and were killed by aggressive strains. These strains expressed high levels of toxins, and possessed the ability to escape from phagolysosomes. Osteoblasts and keratinocytes ingested less bacteria, and were not killed, even though the primary osteoblasts were strongly activated by S. aureus. In all cell types S. aureus was able to persist. Strong differences in uptake, cytotoxicity, and inflammatory response were observed between primary cells and their corresponding cell lines, demonstrating that cell lines reflect only partially the functions and physiology of primary cells. This study provides a contribution for a better understanding of the pathomechanisms of S. aureus infections. The proteomic data provide important basic knowledge on strains commonly used in the analysis of S. aureus-host cell interaction.

ObjectivesThe aim of this study was to introduce cervical strain elastography to objectively assess the cervical tissue transformation process during induction of labour (IOL) and to evaluate the potential of cervical elastography as a predictor of successful IOL.MethodsA total of 41 patients with full-term pregnancies elected for an IOL were included. Vaginal ultrasound with measurement of cervical length and elastography and assessment of the Bishop Score were performed before and 3 h after IOL. The measured parameters were correlated to the outcome of IOL and the time until delivery.ResultsWe observed an association between the strain pattern and the value of the strain ratio 3 h after IOL and a successful IOL (p=0.0343 and p=0.0342, respectively) which can be well demonstrated by the results after 48 h. In our study population the cervical length and the Bishop Score did not prove to be relevant parameters for the prediction of a successful IOL.ConclusionsWe demonstrated for the first time that the cervical elastography pattern after the first prostaglandine application can help predict the outcome of IOL.

To determine the prevalence of multidrug resistant (MDR) bacteria in a cohort of pregnant refugee women. In a prospective case control study, surveillance cultures for MDR bacteria (methicillin-resistant Staphylococcus aureus [MRSA], vancomycin-resistant enterococci [VRE], MDR Gram-negative bacteria [MRGN]) were analysed between October 2015 and June 2016 from a cohort of 50 pregnant refugee women and 50 resident controls in the obstetric unit of a German tertiary referral hospital. Prevalence of MRSA was noticeably higher among refugee women compared to residents (6 vs. 0%). In addition, a trend towards a higher prevalence of VRE and MDR Gram-negative bacteria in refugees was shown (1.8 vs. 0%). Due to the higher prevalence of MDR bacteria, surveillance cultures are justified in order to prevent nosocomial spread of MDR bacteria.

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Virtual poster abstractsObjectives: To evaluate whether serial change in cervical length (CL) over time can be a predictor for massive postpartum bleeding in patients with placenta previa. Methods: This was a retrospective cohort study of patients with placenta previa between January 2014 and November 2019. All women were offered serial measurement of CL by transvaginal ultrasound at 19-23 weeks (CL1), 24-28 weeks (CL2), 29-31 weeks (CL3) and 32-34 weeks (CL4). We compared clinical characteristics, serial change in CL, and outcomes between the massive postpartum bleeding group (case group) and control group. The predictive value of change in CL for emergency CS was evaluated. Results: A total of 93 women were evaluated; 31 had emergency CS due to massive vaginal bleeding. CL tended to decrease with advancing gestational age in each group. Until 29-31 weeks, CL showed no significant differences between the two groups, but after that, CL in the postpartum bleeding group decreased abruptly, even though CL in the control group continued to gradually decrease. On multivariate analysis to determine risk factors, only anterior placenta and change in CL were significantly associated with massive postpartum bleeding. Conclusions: CL should be included in the assessment of a placenta previa given its relationship to intraoperative blood loss.