Genomics of Invasive Cutibacterium acnes Isolates from Deep-Seated Infections

Cutibacterium acnes, formerly known as Propionibacterium acnes, is a commensal of the human pilosebaceous unit but also causes deep-seated infection, especially in the context of orthopedic and neurosurgical foreign materials. Interestingly, little is known about the role of specific pathogenicity factors for infection establishment. Here, 86 infection-associated and 103 commensalism-associated isolates of C. acnes were collected from three independent microbiology laboratories. We sequenced the whole genomes of the isolates for genotyping and a genome-wide association study (GWAS). We found that C. acnes subsp. acnes IA1 was the most significant phylotype among the infection isolates (48.3% of all infection isolates; odds ratio [OR] = 1.98 for infection). Among the commensal isolates, C. acnes subsp. acnes IB was the most significant phylotype (40.8% of all commensal isolates; OR = 0.5 for infection). Interestingly, C. acnes subsp. elongatum (III) was rare overall and did not occur at all in infection. The open reading frame-based GWAS (ORF-GWAS) did not show any loci with a strong signal for infection association (no P values of ≤0.05 after adjustment for multiple testing; no logarithmic OR [logOR] of ≥|2|). We concluded that all subspecies and phylotypes of C. acnes, possibly with the exception of C. acnes subsp. elongatum, are able to cause deep-seated infection given favorable conditions, most importantly related to inserted foreign material. Genetic content appears to have a small effect on the likelihood of infection establishment, and functional studies are needed to understand the individual factors contributing to deep-seated infections caused by C. acnes. IMPORTANCE Opportunistic infections emerging from human skin microbiota are of ever-increasing importance. Cutibacterium acnes, being abundant on the human skin, may cause deep-seated infections (e.g., device-associated infections). Differentiation between invasive (i.e., clinically significant) C. acnes isolates and sole contaminants is often difficult. Identification of genetic markers associated with invasiveness not only would strengthen our knowledge related to pathogenesis but also could open ways to selectively categorize invasive and contaminating isolates in the clinical microbiology lab. We show that in contrast to other opportunistic pathogens (e.g., Staphylococcus epidermidis), invasiveness is apparently a broadly distributed ability across almost all C. acnes subspecies and phylotypes. Thus, our work strongly supports an approach in which clinical significance is judged from clinical context rather than by detecting specific genetic traits.

First case of bloodstream infection caused by Mixta hanseatica sp. nov., a novel species within the Mixta genus of the Erwiniaceae family

Members of the Erwiniaceae family very rarely cause infections in humans. Here we describe the first case of a bloodstream infection due to Mixta hanseatica sp. nov., a novel member of the Erwiniaceae family.

P-121 Azoospermia: are there neonatal differences regarding the source of sperm for ICSI?

Study question

In couples with azoospermia undergoing intracytoplasmic sperm injection (ICSI), are neonatal outcomes different depending on sperm origin (epididymal-PESA, testicular-TESA or donor sperm)?

Summary answer

Newborns from PESA or TESA had similar neonatal outcomes. Comparing to donor cases, PESA/TESA cycles didn’t present increased levels of malformation or stillbirth.

What is known already

Since the introduction of ICSI and the demonstration that the spermatozoa derived either from the epididymis or the testis were capable of normal fertilization and pregnancy, it was possible for azoospermic men to father their own children. However, it raised concerns that the quality of spermatozoa in terms of DNA damage or maturation when collected from non-ejaculated semen could differ from that collected from ejaculated and whether sperm of different origins will affect the neonatal outcome and safety of ICSI.

Study design, size, duration

Retrospective cohort study performed at a reproductive medicine center, using data from 359 deliveries from 945 cycles of ICSI of couples with infertility due to azoospermia, performed between 1995 and 2021. Data were collected from electronic records.

Participants/materials, setting, methods

A total of 359 deliveries were divided in 3 groups, according to the sperm source: PESA (n = 138), TESA (n = 139) and DONOR (n = 82). A total of 402 newborns were evaluated: PESA (n = 162); TESA (n = 156); DONOR (n = 84). Neonatal outcomes and congenital malformations were analyzed for singletons, twins and triplets separately. Statistical analysis: Anova, chi-square and Fischer test, considering p < 0.05.

Main results and the role of chance

Comparing the 3 groups (PESA, TESA, and donor sperm), the following results were found: The mean birth weight (BW), length and Apgar score > 7 for singletons and twins did not differ between groups; neither did prematurity or extreme prematurity. According to birth percentile, there was a lower rate of small for gestational age (SGA) newborn in the epididymal group (PESA, 1.5% vs. TESA, 8.5% vs. sperm donor, 5.5%, p = 0.004). Also, in 158 twin births, the number of newborns with low birth weight (<2500g) was significantly smaller in the epididymal group (PESA, 32.9% vs. TESA, 62.5%; donor sperm, 73.1%, p = 0.001). There were three stillbirths in triplets (PESA group). We also found six cases of neonatal mortality (one in singleton pregnancy in TESA group, 3 in twins (two in PESA group and one donor sperm group), and two in triplets (one in TESA and one in PESA groups). The total number of congenital malformations was 8 (2.48%) (PESA n = 1, 0.62%; TESA, n = 2, 1.28%, and donor sperm, n = 5, 5.95%, p = 0.02).

Limitations, reasons for caution

The possibility of incomplete medical records is an important limitation to be considered in retrospective studies. Larger studies are important to better assess the risk of malformation in this population.

Wider implications of the findings

In this study, there were no differences on neonatal outcomes regarding the source of sperm used for ICSI, with PESA, TESA and donor groups, as well as congenital malformation. It showed equally safe options with testis, epididymal or ejaculated sperm for azoospermia treatments.

Trial registration number

not applicable

P–463 Patients undergoing elective and onco-fertility preservation respond similarly to controlled ovarian stimulation for fertility preservation

Study question

Is the oocyte vitrification response different in patients undergoing elective and onco-fertility preservation?

Summary answer

Patients undergoing elective and onco-fertility preservation seem to respond similarly to controlled ovarian stimulation for fertility preservation.

What is known already

Age persists as the factor with the most significant impact on the prognosis of female fertility. The ovarian reserve can also be threatened by surgical, radiotherapy or chemotherapy procedures. Thus, maternity delay and the increased incidence of malignant diseases are the most jeopardizing conditions for reproductive potential in women. Studies are still conflicting about oocyte freezing results in patients with and without cancer. Some studies suggest worse outcomes in patients with cancer regarding the number of mature vitrified oocytes when compared to healthy patients whether others show similar response to the ovarian stimulation for fertility preservation in both groups.

Study design, size, duration

Observational, cross-sectional, and historical study using data from 367 who underwent oocyte vitrification from a Reproductive Medicine Center, between 2009 and 2018.

Participants/materials, setting, methods

Patients were divided into an elective group (EG; n = 327) and an onco-fertility group (OFG; n = 40). Data were presented as mean ± standard deviation or median and interquartile range (IQR) and absolute and relative frequencies. Chi-square test, Student’s t-test, or Mann-Whitney test were applied. Generalized linear models were used to control confounding factors. Data were adjusted by women age, FSH, and GnRH protocol. The null hypothesis was rejected when p < 0.05. Main results and the role of chance: Patients age in OFG was significantly lower compared to EG (31.3±5.8 vs. 37.0 ±2.9 years; p < 0.01) and also FSH measurement (4.0 [3.3 – 6.2] vs. 9.0 (5.4 – 9.9) mIU/mL; p < 0.01). The presence of a partner was significantly higher in OFG (25 [62.5%] vs. [19.9%]; p < 0.001). GnRH antagonist protocol was used in 80.1% of cycles, and FSH-r was used in 80.4% of cycles. Letrozole was added for 20 breast cancer patients (74%). When adjusting data for age, FSH and Gonadotropin-releasing Hormone (GnRH) protocols, no significant difference in the number of vitrified mature oocytes between the two groups were observed (6.0 [3.0–11.0] vs. 7.0 [3.0–12.0]; p = 0.11). Limitations, reasons for caution: The number of women in the OFG was lower than the EG group. The OFG was composed of different types of tumors in different locations and stages. Thus, it can be questioned whether any patient with a more aggressive tumor might have had a negative impact on the results.

Wider implications of the findings: Healthy patients and patients with cancer seem to respond similarly to ovarian stimulation for fertility preservation. The extensive number of cycles performed for EG in contrast to OFG leads to a reflection on patients who are still not referred for reproductive counseling after a cancer diagnosis.

Trial registration number

Not applicable

P–334 CT virtual Histerotomography: a new method for the evaluation of fallopian tube patency and pelvic organs in patients seeking pregnancy

Study question

Can computerized virtual histerotomography (CT-HSG) be used for the evaluation of fallopian tube patency and pelvic organs in patients seeking pregnancy? Summary answer: CT-HSG seems to be an adequate test for the evaluation of fallopian tube patency, pelvic organs, and the uterine cavity.

What is known already

CT-HSG is a minimally invasive exam, which diagnoses variations in the female reproductive system, uses low radiation doses and is well tolerated by patients. It simultaneously evaluates the uterine wall, cavity and cervix, tubes, and adjacent pelvic structures. The exam enables virtual navigation, which consists of the endoluminal view of the cervical canal and uterine cavity and allows 3D reconstruction of images. The exam remains underused to assess infertility, but previous studies have shown potential and its use may be widespread.

Study design, size, duration

Retrospective cohort study, that included data from 317 women seeking pregnancy, between January/2019 and January/2021. The CT-HSG was indicated for infertility (90.3%) and RPL (0.9%) investigation, and for the evaluation of tubal stump in patients who were planning the tubal reversal surgery (8.8%). Patients filled out a questionnaire about their pain symptoms and data were collected from electronic records.

Participants/materials, setting, methods

The study analyzed patients’ clinical characteristics and image findings regarding tubes, uterine cavity, and ovaries. For the exam, a catheter was positioned in the cervix, where the contrast medium (iopromide) was injected through an infusion pump at 0.30 ml/s, for a total of 20ml. The tomographic slices were obtained at the 50th second. The CT-HSG images were interpreted by the same gynecologist and radiologist. Data were analyzed using SPSS version 20.0.

Main results and the role of chance

Women and partners’ mean age was 32.7 ± 5.6 and 34.6 ± 7.7 years, respectively, and women’s mean BMI was 28.4 ± 6.4 Kg/m². The pain scale was applied in 103 patients, who reported 5.4±3.2 pain scale scores at the end of the exam. Among the infertile patients 67% were nulliparous. Regarding the exam findings, most of the uterus findings were normal (72.6%). The variations found were uterine malformations (including unicornuate uterus, uterus didelphys, bicornuate uterus, septate uterus, and arcuate uterus), synechia, fibroids, endometrial polyps, adenomyosis and retractions/lateralizations that may suggest endometriosis. The tubal findings on the right/left (%) were: 65/67.5 patent horn; 18.9/17.7 obstructed tubes; 4/41 dilatation/hydrosalpinx and 9.4/9.1 with previous history of tubal ligation or salpingectomy; 1.5% of the tubal evaluation were inconclusive. Eleven from 317 patients had to repeat the exam due to occurrences during the execution (for example, improper catheter positioning, cuff fall, stenosis of the internal cervical ostium, severe pain).The 3D analysis and virtual navigation assist in the findings assessment, in addition to being simpler for the gynecologists evaluation.

Limitations, reasons for caution

The sample size is small due to the exam being a new technique. Patient follow-up and correlation with laparoscopy and hysteroscopy, when indicated, are under studied.

Wider implications of the findings: The exam seems to be promising for assessing infertility, RPL and the tubal stump. Moreover, it may be a good option to hysterosalpingography as it seems to cause less pain and allows to evaluate the ovaries and the uterine contour, added to 3D reconstructions and to virtual uterine navigation.

Trial registration number

Not applicable

P–165 Using Artificial Intelligence to Classify Embryo Shape: An International Perspective

Study question

Is a pre-trained machine learning algorithm able to accurately detect cellular arrangement in 4-cell embryos from a different continent?

Summary answer

Artificial Intelligence (AI) analysis of 4-cell embryo classification is transferable across clinics globally with 79% accuracy.

What is known already

Previous studies observing four-cell human embryo configurations have demonstrated that non-tetrahedral embryos (embryos in which cells make contact with fewer than 3 other cells) are associated with compromised blastulation and implantation potential. Previous research by this study group has indicated the efficacy of AI models in classification of tetrahedral and non-tetrahedral embryos with 87% accuracy, with a database comprising 2 clinics both from the same country (Brazil). This study aims to evaluate the transferability and robustness of this model on blind test data from a different country (France).

Study design, size, duration

The study was a retrospective cohort analysis in which 909 4-cell embryo images (“tetrahedral”, n = 749; “non-tetrahedral”, n = 160) were collected from 3 clinics (2 Brazilian, 1 French). All embryos were captured at the central focal plane using Embryoscope™ time-lapse incubators. The training data consisted solely of embryo images captured in Brazil (586 tetrahedral; 87 non-tetrahedral) and the test data consisted exclusively of embryo images captured in France (163 tetrahedral; 72 non-tetrahedral).

Participants/materials, setting, methods

The embryo images were labelled as either “tetrahedral” or “non-tetrahedral” at their respective clinics. Annotations were then validated by three operators. A ResNet–50 neural network model pretrained on ImageNet was fine-tuned on the training dataset to predict the correct annotation for each image. We used the cross entropy loss function and the RMSprop optimiser (lr = 1e–5). Simple data augmentations (flips and rotations) were used during the training process to help counteract class imbalances.

Main results and the role of chance

Our model was capable of classifying embryos in the blind French test set with 79% accuracy when trained with the Brazilian data. The model had sensitivity of 91% and 51% for tetrahedral and non-tetrahedral embryos respectively; precision was 81% and 73%; F1 score was 86% and 60%; and AUC was 0.61 and 0.64. This represents a 10% decrease in accuracy compared to when the model both trained and tested on different data from the same clinics.

Limitations, reasons for caution

Although strict inclusion and exclusion criteria were used, inter-operator variability may affect the pre-processing stage of the algorithm. Moreover, as only one focal plane was used, ambiguous cases were interpoloated and further annotated. Analysing embryos at multiple focal planes may prove crucial in improving the accuracy of the model.

Wider implications of the findings: Though the use of machine learning models in the analysis of embryo imagery has grown in recent years, there has been concern over their robustness and transferability. While previous results have demonstrated the utility of locally-trained models, our results highlight the potential for models to be implemented across different clinics.

Trial registration number

Not applicable

P–481 COVID–19 pandemic: the emotional impact comparing men and women on assisted reproductive treatment

Study question

How has the COVID–19 pandemic affected the psychological aspects of men and women undergoing reproductive treatments?

Summary answer

The women were more emotionally affected due to the COVID–19 pandemic than men, especially increasing anxiety and fear of not achieving pregnancy.

What is known already

COVID–19 pandemic required changes in behavior and plans of most people worldwide, including patients undergoing assisted reproductive treatment (ART). The reproductive societies recommended immediate cessation of all new fertility treatment cycles, arousing different opinions from patients and providers, concerned that a delay of months may affect clinical outcomes. The fear, social distancing and financial insecurity are enough reasons for worry and anguish, and the uncertainty of resuming plans of parenthood make the scenery even more challenging. Therefore, the psychosocial aspects’ evaluation of these patients during the pandemic is fundamental for better comprehension, management, and reception in this especially challenging moment.

Study design, size, duration

Cross-sectional study using data from a centre of reproductive medicine between June and August 2020. The sample was composed of 120 patients (54 men and 66 women), 14.16% undergoing frozen embryo transfer (FET), 77.5% in vitro fertilization (FIV), 1.6% semen freezing collection and 6.6% oocyte freezing.

Participants/materials, setting, methods

The data were extracted from an electronic questionnaire elaborated by the clinical team, which included questions about the patients’ psychological aspects, applied one day before ART. The answers were compared between men and women,and between the types of ART used by each patient. The statistical analysis was made using the program SPSS for Windows. The Chi-Square test was used to compare the study groups, considering p < 0.05 statistically significant.

Main results and the role of chance

It was observed that 23/54 (42%) of men and 42/66 (63%) of women were at least partially emotionally affected by the pandemic (p = 0.027). Comparing feelings between groups (men and women, respectively) the following results were observed: optimistic (42,1% vs 57,9% p = 0.664), hopeful (32,3% vs 67,7%, p = 0.098), anxious (22,6% vs 77,4%, p = 0.004), calm (60,7% vs 39,3%, p < 0.001). Also, 27% of men and 39.3% of women felt more anguished than normal, which was mostly expressed through anxiety (36.7% vs 63.3%, p = 0.113), followed by irritability (54.5% vs 45.5%, p = 0.421), eating habit change (42.5% vs 56.5, p = 0.962) and sleep disorders (28.6% vs 56.5%, p = 0.215). Most patients (96.6%) reported having somebody to share their feelings and didn’t want to be contacted by the clinic’s psychologist (92.5%); 26.3% of couples had their relationship positively affected. Comparing feelings between patients undergoing FET vs FIV, respectively, were found: optimistic (47.0% vs 29.0%, p = 0.142) and anxious (23,5% vs 27.9%, p = 0.70).

Limitations, reasons for caution

The data was collected at one point, in the worst moment of the pandemic in Brazil, which may have influenced some of the answers. The small sample size is due to the lower number of procedures in this period.

Wider implications of the findings: The feelings were similar between groups. However, women seemed to be more fearful of not being able to realize the parenthood dream. Anxiety was the main symptom in both groups, being more prevalent in women. This study reinforces the importance of having mental health professionals in assisted reproductive clinic.

Trial registration number

Not applicable

P–107 Does hematological cancer have the same impact on sperm quality as testicular cancer?

Study question

Does hematological cancer have the same impact on sperm quality as testicular cancer before chemo or radiotherapy? Summary answer: Hematological cancer has no impact on sperm quality before treatment.

What is known already

The deleterious effects of chemo and radiotherapy on testicular function are well known. Furthermore, testicular cancer causes a negative impact on sperm quality, even before treatment, probably due to local action. Hematological cancer, particularly Hodgkin lymphoma, seems to produce inflammatory alterations in the testis. However, it is not clear if hematological cancer can compromise spermatogenesis, as does testicular cancer.

Study design, size, duration

Observational, cross-sectional, retrospective study using data from 360 patients seen at a private infertility clinic between 1992 and 2019 for sperm cryopreservation before treatment. The data were collected from electronic records in a prospective database.

Participants/materials, setting, methods

Seminal samples from patients that cryopreserved semen due to hematological or testicular cancer were compared. Sperm analyses were performed according to the 2010’s World Health Organization (WHO)’s parameters. Seminal volume, total sperm number, sperm concentration, total and progressive motility, and vitality were analysed. In the hematological group, leukemia and lymphoma, and Hodgkin and non-Hodgkin lymphoma were compared. Student t-tests and Chi-Square were used, considering p < 0.05 statistically significant.

Main results and the role of chance

This study included 295 patients with testicular cancer (TEST) and 100 with hematological cancer (HEMAT). Patients that had already started chemo or radiotherapy (4 HEMAT and 12 TEST) were excluded, and 4 HEMAT and 15 TEST were azoospermic or cryptozoospermic (41.7% vs. 53,0%, p = 0,792 ). The other parameters were analysed in 92 HEMAT and 268 TEST. The mean age of the HEMAT group was 28.2 years and 27.9 for the TEST group (p = 0,858). The TEST group had higher rates of oligozoospermia (50.7% vs 31.5%, p = 0.001) and of severe oligozoospermia (29.5% vs 15.2%, p = 0.006) than the HEMAT group. Furthermore, 69.6% HEMAT had normal concentration, compared to 45.9% TEST (p < 0.001). The mean concentration of the HEMAT group was 35 mi/mL, normal according to the WHO’s standards, and the TEST group was 12 mi/mL, below the WHO’s normal standards (p < 0.001). No difference was found when comparing leukemia and lymphoma, or Hodgkin and non-Hodgkin lymphoma.

Limitations, reasons for caution

Besides the fact that this study is retrospective, it also has a small sample size. Furthermore, no analyses regarding sperm morphology were made.

Wider implications of the findings: In this study, testicular cancer had a negative impact on spermatogenesis and sperm quality, whereas hematological cancer did not. However, counseling regarding fertility preservation using sperm banking prior to chemo or radiotherapy should be reinforced in all young cancer patients.

Trial registration number

Not applicable

Tandem Affinity Purification of SBP-CBP-tagged Type Three Secretion System Effectors

Identification of protein-protein interactions of bacterial effectors and cellular targets during infection is at the core to understand how bacteria manipulate the infected host to overcome the immune response. Potential interacting proteins might be identified by genetic methods, i.e., two hybrid screens and could be verified by co-immunoprecipitation. The tandem affinity purification (TAP) method allows an unbiased screen of potential interaction partners of bacterial effectors in a physiological approach: target cells can be infected with a bacterial strain harboring the TAP-tagged bacterial effector protein which is translocated in the host similar as under physiological infection conditions. No transfection and overexpression of the bacterial protein in the eukaryotic host are needed. Therefore, also host target cells not easy to transfect can be analyzed by this method. Moreover, the two consecutive affinity tags Calmodulin-Binding-Peptide (CBP) and Streptavidin-Binding-Peptide (SBP) fused to the translocated bacterial protein allow an outstanding clear purification of protein complexes formed between the bacterial protein of interest and host cell proteins with less occurrence of contaminants. Mass spectrometry allows an unbiased identification of interacting eukaryotic proteins.

Molecular analysis of the ramRA locus in clinical Klebsiella pneumoniae isolates with reduced susceptibility to tigecycline

Mutations in ramR, a negative regulator of ramA which stimulates transcription of acrA/-B encoding the multidrug efflux pump AcrAB-TolC, were recently shown to result in reduced susceptibility to tigecycline in Klebsiella pneumoniae. We analysed six non-duplicate K. pneumoniae isolates with elevated MICs to tigecycline. All isolates showed transcriptional up-regulation of ramA and acrB as demonstrated by Northern blot and quantitative real-time PCR. Sequencing of the ramR gene revealed deletions in five of the isolates and a premature stop codon in one isolate. Transformation of the wild-type ramR gene but not of any of the detected mutant ramR genes into a ramR-mutant K. pneumoniae strain restored tigecycline susceptibility and repressed ramA and acrB transcription to wild type levels. Thus, our study confirms the role of inactivating mutations in the ramR gene in tigecycline resistance.

Advances in Rapid Identification and Susceptibility Testing of Bacteria in the Clinical Microbiology Laboratory: Implications for Patient Care and Antimicrobial Stewardship Programs

Early availability of information on bacterial pathogens and their antimicrobial susceptibility is of key importance for the management of infectious diseases patients. Currently, using traditional approaches, it usually takes at least 48 hours for identification and susceptibility testing of bacterial pathogens. Therefore, the slowness of diagnostic procedures drives prolongation of empiric, potentially inappropriate, antibacterial therapies. Over the last couple of years, the improvement of available techniques (e.g. for susceptibility testing, DNA amplification assays), and introduction of novel technologies (e.g. MALDI-TOF) has fundamentally changed approaches towards pathogen identification and characterization. Importantly, these techniques offer increased diagnostic resolution while at the same time shorten the time-to-result, and are thus of obvious importance for antimicrobial stewardship. In this review, we will discuss recent advances in medical microbiology with special emphasis on the impact of novel techniques on antimicrobial stewardship programs.

[Advances in diagnostic microbiology : Opportunities and limitations]

In the light of ever increasing problems related to the emergence of multidrug-resistant bacteria, rapid microbiological diagnostics are of growing importance. Timely pathogen detection and availability of susceptibility data are essential for optimal treatment, but are even more crucial for de-escalation of broad spectrum empiric therapies. Medical microbiology is, thus, an integral part of antimicrobial stewardship programs. Traditional microbiological techniques for species identification and susceptibility testing rely on bacterial growth and are, thus, characterized by inherent slowness. Time-to-report is usually 48 h or longer, and typically delays optimization of therapeutic regimens. Constant improvement of available techniques (e. g., molecular methods) and introduction of novel methods (e. g., matrix-assisted laser desorption ionization time-of-flight [MALDI-ToF] mass spectrometry) have fundamentally changed diagnostic procedures. As a consequence, sensitivity and specificity as well as time-to-report have been dramatically improved. In this manuscript, key methodological advances in medical microbiology are discussed, emphasizing consequences for daily management of infectious disease patients.

First report of Escherichia coli co-producing NDM-1 and OXA-232

Recently Gram-negative bacteria co-producing multiple carbapenemases have emerged in different parts of the world. We report the first isolation of an Escherichia coli strain co-producing the carbapenemases NDM-1 and OXA-232.

Immunosuppressive Yersinia Effector YopM Binds DEAD Box Helicase DDX3 to Control Ribosomal S6 Kinase in the Nucleus of Host Cells

Yersinia outer protein M (YopM) is a crucial immunosuppressive effector of the plaque agent Yersinia pestis and other pathogenic Yersinia species. YopM enters the nucleus of host cells but neither the mechanisms governing its nucleocytoplasmic shuttling nor its intranuclear activities are known. Here we identify the DEAD-box helicase 3 (DDX3) as a novel interaction partner of Y. enterocolitica YopM and present the three-dimensional structure of a YopM:DDX3 complex. Knockdown of DDX3 or inhibition of the exportin chromosomal maintenance 1 (CRM1) increased the nuclear level of YopM suggesting that YopM exploits DDX3 to exit the nucleus via the CRM1 export pathway. Increased nuclear YopM levels caused enhanced phosphorylation of Ribosomal S6 Kinase 1 (RSK1) in the nucleus. In Y. enterocolitica infected primary human macrophages YopM increased the level of Interleukin-10 (IL-10) mRNA and this effect required interaction of YopM with RSK and was enhanced by blocking YopM's nuclear export. We propose that the DDX3/CRM1 mediated nucleocytoplasmic shuttling of YopM determines the extent of phosphorylation of RSK in the nucleus to control transcription of immunosuppressive cytokines.

Prevalence and genotypes of extended spectrum beta-lactamases in Enterobacteriaceae isolated from human stool and chicken meat in Hamburg, Germany

Chicken meat has been proposed to constitute a source for extended spectrum beta-lactamase (ESBL)-carrying Enterobacteriaceae that colonize and infect humans. In this study the prevalence of ESBL-producing Enterobacteriaceae in stool samples from ambulatory patients who presented in the emergency department of the University Medical Centre Hamburg-Eppendorf with gastrointestinal complains and in chicken meat samples from the Hamburg region were analysed and compared with respect to ESBL-genotypes, sequence types and antibiotic resistance profiles. Twenty-nine (4.1%) of 707 stool samples and 72 (60%) of 120 chicken meat samples were positive for ESBL-producing Enterobacteriaceae. The distribution of ESBL genes in the stool vs. chicken meat isolates (given as % of total isolates from stool vs. chicken meat) was as follows: CTX-M-15 (38% vs. 0%), CTX-M-14 (17% vs. 6%), CTX-M-1 (17% vs. 69%), SHV-12 (3% vs. 18%) and TEM-52 (3% each). Comparison of ESBL- and multilocus sequence type revealed no correlation between isolates of human and chicken. Furthermore, ESBL-producing E. coli from stool samples were significantly more resistant to fluoroquinolones, aminoglycosides and/or trimethoprim-sulfamethoxazole than chicken isolates. The differences in ESBL-genotypes, sequence types and antibiotic resistance patterns indicate that in our clinical setting chicken meat is not a major contributor to human colonization with ESBL-carrying Enterobacteriaceae.

Open-source genomic analysis of Shiga-toxin-producing E. coli O104:H4

An outbreak caused by Shiga-toxin–producing Escherichia coli O104:H4 occurred in Germany in May and June of 2011, with more than 3000 persons infected. Here, we report a cluster of cases associated with a single family and describe an open-source genomic analysis of an isolate from one member of the family. This analysis involved the use of rapid, bench-top DNA sequencing technology, open-source data release, and prompt crowd-sourced analyses. In less than a week, these studies revealed that the outbreak strain belonged to an enteroaggregative E. coli lineage that had acquired genes for Shiga toxin 2 and for antibiotic resistance.

Activity modulation of the bacterial Rho GAP YopE: an inspiration for the investigation of mammalian Rho GAPs

The Yersinia enterocolitica Rho GTPase Activating Protein (Rho GAP) YopE belongs to a group of bacterial virulence factors that is translocated into infected target cells by a type three secretion system. Structurally and biochemically YopE resembles eukaryotic Rho GAPs which control various cellular functions by modulating the activity of Rho GTP binding proteins. Here we summarise the published information on cellular effects, Rho protein substrates, compartmentalisation and turnover of YopE. A fascinating picture evolves of how this virulence factor integrates in host cellular regulatory mechanisms to fine tune bacterial pathogenicity.

Yersinia virulence factor YopM induces sustained RSK activation by interfering with dephosphorylation

Background

Pathogenic yersiniae inject several effector proteins (Yops) into host cells, which subverts immune functions and enables the bacteria to survive within the host organism. YopM, whose deletion in enteropathogenic yersiniae results in a dramatic loss of virulence, has previously been shown to form a complex with and activate the multifunctional kinases PKN2 and RSK1 in transfected cells.

Methodology/Principal Findings

In a near physiological approach with double-affinity-tagged YopM being translocated into the macrophage cell line J774A.1 via the natural type three secretion system of Yersinia we verified the interaction of YopM with PKN2 and RSK1 and detected association with additional PKN and RSK isoforms. In transfected and infected cells YopM induced sustained phosphorylation of RSK at its activation sites serine-380 and serine-221 even in the absence of signalling from its upstream kinase ERK1/2, suggesting inhibition of dephosphorylation. ATP-depletion and in vitro assays using purified components directly confirmed that YopM shields RSK isoforms from phosphatase activity towards serines 380 and 221.

Conclusions/Significance

Our study suggests that during Yersinia infection YopM induces sustained activation of RSK by blocking dephosphorylation of its activatory phosphorylation sites. This may represent a novel mode of action of a bacterial virulence factor.

Nuclear factor I-A represses expression of the cell adhesion molecule L1

BACKGROUND

The neural cell adhesion molecule L1 plays a crucial role in development and plasticity of the nervous system. Neural cells thus require precise control of L1 expression.

RESULTS

We identified a full binding site for nuclear factor I (NFI) transcription factors in the regulatory region of the mouse L1 gene. Electrophoretic mobility shift assay (EMSA) showed binding of nuclear factor I-A (NFI-A) to this site. Moreover, for a brain-specific isoform of NFI-A (NFI-A bs), we confirmed the interaction in vivo using chromatin immunoprecipitation (ChIP). Reporter gene assays showed that in neuroblastoma cells, overexpression of NFI-A bs repressed L1 expression threefold.

CONCLUSION

Our findings suggest that NFI-A, in particular its brain-specific isoform, represses L1 gene expression, and might act as a second silencer of L1 in addition to the neural restrictive silencer factor (NRSF).

The murine AE4 promoter predominantly drives type B intercalated cell specific transcription

AE4 is an anion exchanger almost exclusively expressed in the collecting ducts of the kidney. This very restricted expression prompted us to analyze its transcription in more detail. 5' RACE yielded alternative transcriptional start sites that are predicted to code for N-terminal protein variants. Comparison of the 5' genomic sequence between species identified a transcriptionally active region with three conserved spans. In transgenic mice beta-galactosidase expression driven by this fragment resembled endogenous AE4 expression and was predominantly restricted to type B intercalated cells. Hence this promoter could prove useful to target type B intercalated cells by genetic approaches.

Yersinia enterocolitica differentially modulates RhoG activity in host cells

Pathogenic bacteria of the genus Yersinia (Y. pestis, Y. enterocolitica and Y. pseudotuberculosis) have evolved numerous virulence factors (termed a stratagem) to manipulate the activity of Rho GTPases. Here, we show that Y. enterocolitica modulates RhoG, an upstream regulator of other Rho GTPases. At the contact site of virulent Y. enterocolitica and host cells, we could visualise spatiotemporally organised activation and deactivation of RhoG. On the one hand, the beta1-integrin clustering protein Invasin on the bacterial surface was found to activate RhoG and this promoted cell invasion. On the other hand, active RhoG was downregulated by the type III secretion system effector YopE acting as a GTPase-activating protein (GAP). YopE localised to Golgi and endoplasmic reticulum, and this determined its specificity for RhoG and other selected Rho GTPases. RhoG and its downstream effector module Elmo/Dock180 controlled both Rac1 activation by Invasin and Rac1 deactivation by YopE. We propose that RhoG is a central target of the Yersinia stratagem and a major upstream regulator of Rac1 during different phases of the Yersinia infection cycle.

Serogroup-related escape of Yersinia enterocolitica YopE from degradation by the ubiquitin-proteasome pathway

Pathogenic Yersinia spp. employ a type III protein secretion system that translocates several Yersinia outer proteins (Yops) into the host cell to modify the host immune response. One strategy of the infected host cell to resist the bacterial attack is degradation and inactivation of injected bacterial virulence proteins through the ubiquitin-proteasome pathway. The cytotoxin YopE is a known target protein of this major proteolytic system in eukaryotic cells. Here, we investigated the sensitivity of YopE belonging to different enteropathogenic Yersinia enterocolitica serogroups to ubiquitination and proteasomal degradation. Analysis of the YopE protein levels in proteasome inhibitor-treated versus untreated cells revealed that YopE from the highly pathogenic Y. enterocolitica serotype O8 was subjected to proteasomal destabilization, whereas the YopE isotypes from serogroups O3 and O9 evaded degradation. Accumulation of YopE from serotypes O3 and O9 was accompanied by an enhanced cytotoxic effect. Using Yersinia strains that specifically produced YopE from either Y. enterocolitica O8 or O9, we found that only the YopE protein from serogroup O8 was modified by polyubiquitination, although both YopE isotypes were highly homologous. We determined two unique N-terminal lysines (K62 and K75) in serogroup O8 YopE, not present in serogroup O9 YopE, that served as polyubiquitin acceptor sites. Insertion of either lysine in serotype O9 YopE enabled its ubiquitination and destabilization. These results define a serotype-dependent difference in the stability and activity of the Yersinia effector protein YopE that could influence Y. enterocolitica pathogenesis.

Germ cell nuclear factor is a repressor of CRIPTO-1 and CRIPTO-3

The pluripotency of embryonic stem and embryonic carcinoma cells is maintained by the expression of a set of "stemness" genes. Whereas these genes are down-regulated upon induction of differentiation, the germ cell nuclear factor (GCNF) is transiently up-regulated and represses several pluripotency genes. CRIPTO-1, a co-receptor for the morphogen nodal, is strongly expressed in undifferentiated cells and is rapidly down-regulated during retinoic acid-induced differentiation. Although CRIPTO-1 is expressed at very low levels in adult tissues under normal conditions, it is found highly expressed in a broad range of tumors, where it acts as a potent oncogene. We show that expression of CRIPTO-1 is directly repressed by GCNF during differentiation of the human teratocarcinoma cell line, NT2. GCNF bound to a DR0 element of the CRIPTO-1 promoter in vitro, as shown by electrophoretic mobility shift assays, and in vivo, as demonstrated by chromatin immunoprecipitation. Reporter gene assays demonstrated that GCNF-mediated repression of the CRIPTO-1 promoter is dependent upon the DR0 site. Overexpression of GCNF in NT2 cells resulted in repression of CRIPTO-1 transcription, whereas expression of the transcription-activating fusion construct GCNF-VP16 led to an induction of the CRIPTO-1 gene and prevented its retinoic acid-induced down-regulation. Furthermore, we demonstrated that CRIPTO-3, a processed pseudogene of CRIPTO-1 on the X chromosome, is expressed in undifferentiated NT2 cells and is regulated by GCNF in parallel to CRIPTO-1. Thus, our study supports the hypothesis of GCNF playing a central role during differentiation of stem cells by repression of stem cell-specific genes.

Fabry disease in a female patient due to a de novo point mutation at position 691 of exon 5

Fabry disease is an X-linked lysosomal disorder caused by deficiency of the lysosomal enzyme alpha-galactosidase A. We report on a 32-year-old female patient with an 8-year history of vascular lesions on the hips and periumbilical region and a presumed Fabry disease without positive family history. Ophthalmologic evaluation revealed whorl-like corneal opacities. Echocardiography revealed myxomatous degeneration and prolapse of the mitral valve. DNA analysis of the alpha-galactosidase A gene confirmed the diagnosis of Fabry disease, showing a de novo point mutation at position 691 of exon 5. The patient is now obtaining intravenous enzyme replacement therapy with agalsidase alfa and remains without drug-related reactions.

Manifestation des Morbus Fabry bei einer heterozygoten Anlageträgerin

HISTORY AND ADMISSION FINDINGS

A 32-year-old woman with bilateral corneal opacities was at 9 years of age diagnosed to have reduced activity of the enzyme alpha-galactosidase A. She was admitted to our hospital because of skin lesions that had developed over the last 8 years.

INVESTIGATIONS

The clinical features included angiokeratomas on the buttocks, hips, and periumbilical region, whorl-like corneal opacity (cornea verticillata), and mitral valve prolapse. Activity of alpha-galactosidase A was reduced to about a quarter of the normal value. Histological examination revealed lipid deposits within the endothelial cells of the skin. Molecular analysis of the alpha-galactosidase A gene revealed a point mutation at nucleotide-position 691 in exon 5 (p.Asp231Asn).

TREATMENT AND COURSE

Enzyme replacement therapy with agalsidase alfa 0.2 mg/kg body-weight, infused over 40 min every other week, was initiated. So far no side effects due to the infusion therapy have been noted. The therapeutic success (reduction of lipid storage) cannot be assessed as yet.

CONCLUSION

Fabry disease results from deficient activity of the enzyme alpha-galactosidase A. Affected (hemizygous) males often show the complete spectrum of symptoms and signs and have a deficient alpha-galactosidase A activity. Occasionally milder oligosymptomatic courses are observed, when residual enzyme activity is present. In contrast to previous belief, heterozygous females may be affected in the same manner as hemizygotes and may also have a significantly reduced enzyme activity.

Mice with a targeted disruption of the Cl-/HCO3- exchanger AE3 display a reduced seizure threshold

Neuronal activity results in significant pH shifts in neurons, glia, and interstitial space. Several transport mechanisms are involved in the fine-tuning and regulation of extra- and intracellular pH. The sodium-independent electroneutral anion exchangers (AEs) exchange intracellular bicarbonate for extracellular chloride and thereby lower the intracellular pH. Recently, a significant association was found with the variant Ala867Asp of the anion exchanger AE3, which is predominantly expressed in brain and heart, in a large cohort of patients with idiopathic generalized epilepsy. To analyze a possible involvement of AE3 dysfunction in the pathogenesis of seizures, we generated an AE3-knockout mouse model by targeted disruption of Slc4a3. AE3-knockout mice were apparently healthy, and neither displayed gross histological and behavioral abnormalities nor spontaneous seizures or spike wave complexes in electrocorticograms. However, the seizure threshold of AE3-knockout mice exposed to bicuculline, pentylenetetrazole, or pilocarpine was reduced, and seizure-induced mortality was significantly increased compared to wild-type littermates. In the pyramidal cell layer of the hippocampal CA3 region, where AE3 is strongly expressed, disruption of AE3 abolished sodium-independent chloride-bicarbonate exchange. These findings strongly support the hypothesis that AE3 modulates seizure susceptibility and, therefore, are of significance for understanding the role of intracellular pH in epilepsy.

The forkhead transcription factor Foxi1 directly activates the AE4 promoter

Intercalated cells are highly specialized cells within the renal collecting duct epithelium and play an important role in systemic acid-base homoeostasis. Whereas type A intercalated cells secrete protons via an apically localized H+-ATPase, type B intercalated cells secrete HCO3-. Type B intercalated cells specifically express the HCO3-/Cl- exchanger AE4 (anion exchanger 4), encoded by Slc4a9. Mice with a targeted disruption of the gene for the forkhead transcription factor Foxi1 display renal tubular acidosis due to an intercalated cell-differentiation defect. Collecting duct cells in these mice are characterized by the absence of inter-calated cell markers including AE4. To test whether Slc4a9 is a direct target gene of Foxi1, an AE4 promoter construct was generated for a cell-based reporter gene assay. Co-transfection with the Foxi1 cDNA resulted in an approx. 100-fold activation of the AE4 promoter construct. By truncating the AE4 promoter at the 5'-end, we demonstrate that a fragment of approx. 462 bp upstream of the transcription start point is sufficient to mediate activation by Foxi1. Sequence analysis of this region revealed at least eight potential binding sites for Foxi1 in both sense and antisense orientation. Only one element was bound by recombinant Foxi1 protein in bandshift assays. Mutation of this site abolished both binding in bandshift assays and transcriptional activation by co-transfection of Foxi1 in the reporter gene assay. We thus identify the AE4 promoter as a direct target of Foxi1.

Expression of the sodium-driven chloride bicarbonate exchanger NCBE during prenatal mouse development

In the immature central nervous system (CNS) GABA-mediated excitation is thought to be an important developmental signal. It depends on a high intracellular chloride concentration ([Cl(-)](i)) of the particular neuron. [Cl(-)](i) is a consequence of chloride transport processes across the plasma membrane. The ongoing expression of the KCl-co-transporter KCC2 eventually lowers [Cl(-)](i) in most CNS neurons and thus renders GABA hyperpolarizing. As NCBE, a sodium-dependent chloride-bicarbonate exchanger, also lowers [Cl(-)](i) and may thus modulate the GABA-response, we analyzed its expression during prenatal mouse development before establishment of the mature KCC2 expression. Indeed, NCBE is expressed very early in CNS neurons and precedes the expression of KCC2. Unlike KCC2, NCBE is expressed in the peripheral nervous system and in non-neuronal tissues as the choroid plexus, the dura, and some epithelia including the acid secreting epithelium of the stomach and the duodenal epithelium.

Identification of PNRC2 and TLE1 as activation function-1 cofactors of the orphan nuclear receptor ERRgamma

Estrogen-related receptor gamma (ERRgamma) is an orphan nuclear receptor highly expressed in heart, skeletal muscle, kidney, and brain. To identify activation function-1 (AF-1)-dependent cofactors involved in the transcriptional function of ERRgamma, we screened for human cDNAs coding for proteins that bind to the bacterial expressed AF-1 by biopanning of a phage display library. Phages displaying fusion proteins with full-length PNRC2 (proline-rich nuclear receptor co-regulatory protein 2), already shown to be a cofactor for other nuclear receptors, and with a polypeptide of the bHLH corepressor TLE1 bound to the AF-1 containing bait. Pull-down analyses demonstrated a direct interaction of the receptor with the newly identified full-length proteins. Surprisingly, not only PNRC2 but also the corepressor TLE1 functioned as ERRgamma coactivator in a reporter gene analysis.

Characterization of calmodulin binding to the orphan nuclear receptor Errgamma

The estrogen receptor-related receptor gamma (ERRgamma/ ERR3/NR3B3), a member of the nuclear receptor superfamily, activates transcription in the absence of ligands. In order to identify ligand-independent mechanisms of activation, we tested whether calmodulin (CaM), a key regulator of numerous cellular processes and a predominant intracellular receptor for Ca2+-signals, interacts with ERRgamma. In vitro pull-down experiments with calmodulin-Sepharose demonstrated a Ca2+-dependent interaction with cellularly expressed ERRgamma. As shown by truncation analysis, the CaM binding site is highly unusual in that it is composed of two discontinuous elements. Moreover, by surface plasmon resonance (SPR) biosensor technology, we detected a direct interaction of immobilized bacterially expressed ERR-gamma fusion protein with Ca2+-calmodulin. This is best described by a model which assumes a conformational change of the initially formed complex to a more stable form. Whereas in vitro DNA binding was calmodulin-independent, transient transfection analysis revealed a Ca2+-influx-dependent ERRgamma-mediated transcriptional activation of a luciferase reporter gene. Thus, we propose that CaM acts as a mediator in the Ca2+-dependent modulation of ERRgamma.

PGC-1 and PERC, coactivators of the estrogen receptor-related receptor gamma

The mouse nuclear receptor ERRgamma (estrogen receptor-related receptor gamma) is highly expressed in heart, skeletal muscle, kidney, and brain, as well as in the developing nervous system. We found that the expression of the coactivators PGC-1 (PGC-1alpha) and PERC (PGC-1beta) in mammalian cells augmented potently the transcriptional activation by ERRgamma. The constitutive activation function 2 (AF-2) of the orphan receptor was important for the synergistic enhancement. Functional receptor truncation analysis revealed an additional amino-terminal activation function, specific for the ERRgamma2 isoform and PGC-1. In vitro experiments showed a direct interaction of ERRgamma with both coactivators. Our findings suggest distinct regulatory functions for PGC-1 and PERC as tissue-specific coactivators for ERRgamma.

Domains of ERRgamma that mediate homodimerization and interaction with factors stimulating DNA binding

The estrogen receptor-related receptor gamma (ERRgamma/ERR3/NR3B3) is an orphan member of the nuclear receptor superfamily closely related to the estrogen receptors. To explore the DNA binding characteristics, the protein-DNA interaction was studied in electrophoretic mobility shift assays (EMSAs). In vitro translated ERRgamma binds as a homodimer to direct repeats (DR) without spacing of the nuclear receptor half-site 5'-AGGTCA-3' (DR-0), to extended half-sites, and to the inverted estrogen response element. Using ERRgamma deletion constructs, binding was found to be dependent on the presence of sequences in the ligand binding domain (LBD). A far-Western analysis revealed that ERRgamma forms dimers even in the absence of DNA. Two elements, located in the hinge region and in the LBD, respectively, are necessary for DNA-independent dimerization. DNA binding of bacterial expressed ERRgamma requires additional factors present in the serum and in cellular extracts. Fusion proteins of the germ cell nuclear factor (GCNF/NR6A1) with ERRgamma showed that the characteristic feature to be stimulated by additional factors can be transferred to a heterologous protein. The stimulating activity was further characterized and its target sequence narrowed down to a small element in the hinge region.