Breast cancer awareness messages: investigating response among Lebanese women.

While national Lebanese studies done on breast cancer attest to the importance of awareness campaigns none, however, examine the type of content that most effectively reaches women. The purpose of this study, therefore, was to examine, through an experiment, the effectiveness of direct versus indirect messaging, in altering knowledge, risk perception, attitudes, behaviors and self-efficacy among two groups of women, those aged 18-40 and 41-65 years. Findings suggest that the designed breast cancer communication messages were perceived as informative, trustworthy and believable regardless of message type. An interaction effect indicated that the older age group (41+) who were exposed to the indirect message felt more confident in taking proactive measures than the 18- to 40-year-old participants. In addition, those exposed to the indirect message were more likely to behave as communicated than those in the direct message condition. At the very least, the messages, both direct and indirect, helped minimize misconception or correct people's knowledge about the subject. This shows that participants and by extension people, in general, pay attention to breast cancer awareness messaging. Making these messages available to all age groups and motivating them to take proactive/preventative measures becomes even more significant, especially with the higher incidence of cancer among women aged 18-40 years in Lebanon.

Narrative Exemplars and the Celebrity Spokesperson in Lebanese Anti-Domestic Violence Public Service Announcements.

Domestic violence is a worldwide epidemic. This study examines the effects of narrative exemplars and a celebrity spokesperson in anti-domestic violence ads on Lebanese college students' attitudes and beliefs towards domestic violence and whether these effects are impacted by personal experience. The practical significance is derived from the high prevalence of domestic violence internationally, making it important to find ways to effectively use media to address this health-related issue that has huge consequences for the individual and society. This study adds to the theoretical understanding of narrative persuasion and media effects. Results indicated that narrative exemplars in anti-domestic violence ads promoting bystander awareness and intervention were more beneficial for people without relevant experience compared to people who know someone affected by domestic violence. Anti-domestic violence ads without narrative exemplars, but that also featured an emotional self-efficacy appeal targeting bystanders, were more effective for participants who know someone who had experienced domestic violence compared to participants without relevant experience. The presence of a celebrity spokesperson elicited more positive attitudes about the ad than a noncelebrity, but failed to directly affect relevant anti-domestic violence attitudes or beliefs. These results highlight the significance of formative audience research in health communication message design.

Immunorecognition of Streptococcus mutans secreted proteins protects against caries by limiting tooth adhesion.

INTRODUCTION: Childhood caries, a prevalent chronic disease, affects 60-90 % of children in industrialized regions, leading to lesions in both primary and permanent teeth. This condition precipitates hospital admissions, emergency room visits, elevated treatment costs, and missed school days, thereby impeding the child's academic engagement and increasing the likelihood of caries into adulthood. Despite multiple identified risk factors, significant interpersonal variability remains unexplained. The immune system generates a unique antibody repertoire, essential for maintaining a balanced and healthy oral microbiome. Streptococcus mutans is a primary contributor to the development of caries. METHODS: Employing mass spectrometry, we investigated the S. mutans proteins targeted by antibodies in children both with and without caries, delineating a fundamental suite of proteins discernible by the immune systems of a majority of individuals. Notably, this suite was enriched with proteins pivotal for bacterial adhesion. To ascertain the physiological implications of these discoveries, we evaluated the efficacy of saliva in thwarting S. mutans adherence to dental surfaces. RESULTS: Antibodies in most children recognized a core set of ten S. mutans proteins, with additional proteins identified in some individuals. There was no significant difference in the proteins identified by children with or without caries, but there was variation in antibody binding intensity to some proteins. Functionally, saliva from caries-free individuals, but not children with caries, was found to hinder the binding of S. mutans to teeth. These findings delineate the S. mutans proteome targeted by the immune system and suggest that the inhibition of bacterial adherence to teeth is a primary mechanism employed by the immune system to maintain oral balance and prevent caries formation. CONCLUSIONS: These findings enhance our knowledge of the immune system's function in oral health maintenance and caries prevention, shedding light on how immunoglobulins interact with S. mutans proteins. CLINICAL SIGNIFICANCE: Targeting S. mutans proteins implicated in bacterial adhesion could be a promising strategy for preventing childhood caries.

Bioenergetic State of Escherichia coli Controls Aminoglycoside Susceptibility.

Aminoglycosides (AG) have been used against Gram-negative bacteria for decades. Yet, how bacterial metabolism and environmental conditions modify AG toxicity is poorly understood. Here, we show that the level of AG susceptibility varies depending on the nature of the respiratory chain that Escherichia coli uses for growth, i.e., oxygen, nitrate, or fumarate. We show that all components of the fumarate respiratory chain, namely, hydrogenases 2 and 3, the formate hydrogenlyase complex, menaquinone, and fumarate reductase are required for AG-mediated killing under fumarate respiratory conditions. In addition, we show that the AAA+ ATPase RavA and its Von Wildebrand domain-containing partner, ViaA, are essential for AG to act under fumarate respiratory conditions. This effect was true for all AG that were tested but not for antibiotics from other classes. In addition, we show that the sensitizing effect of RavA-ViaA is due to increased gentamicin uptake in a proton motive force-dependent manner. Interestingly, the sensitizing effect of RavA-ViaA was prominent in poor energy conservation conditions, i.e., with fumarate, but dispensable under high energy conservation conditions, i.e., in the presence of nitrate or oxygen. We propose that RavA-ViaA can facilitate uptake of AG across the membrane in low-energy cellular states. IMPORTANCE Antibiotic resistance is a major public health, social, and economic problem. Aminoglycosides (AG) are known to be highly effective against Gram-negative bacteria, but their use is limited to life-threatening infections because of their nephrotoxicity and ototoxicity at therapeutic dose. Elucidation of AG-sensitization mechanisms in bacteria would allow reduced effective doses of AG. Here, we have identified the molecular components involved in anaerobic fumarate respiration that are required for AG to kill. In addition to oxidoreductases and menaquinone, this includes new molecular players, RavA, an AAA+ ATPase, and ViaA, its partner that has the VWA motif. Remarkably, the influence of RavA-ViaA on AG susceptibility varies according to the type of bioenergetic metabolism used by E. coli. This is a significant advance because anaerobiosis is well known to reduce the antibacterial activity of AG. This study highlights the critical importance of the relationship between culture conditions, metabolism, and antibiotic susceptibility.

Osilodrostat-induced adrenal insufficiency in a patient with Cushing's disease.

Cushing's disease is a rare condition caused by a benign pituitary tumor underlying adrenocorticotropic hormone excess. Medical treatment is implemented when surgical resection is not curative. We present a case of Cushing's disease with recurrence of macroadenoma who developed iatrogenic adrenal insufficiency in the setting of Osilodrostat treatment.

The AAA+ ATPase RavA and its binding partner ViaA modulate E. coli aminoglycoside sensitivity through interaction with the inner membrane.

Enteric bacteria have to adapt to environmental stresses in the human gastrointestinal tract such as acid and nutrient stress, oxygen limitation and exposure to antibiotics. Membrane lipid composition has recently emerged as a key factor for stress adaptation. The E. coli ravA-viaA operon is essential for aminoglycoside bactericidal activity under anaerobiosis but its mechanism of action is unclear. Here we characterise the VWA domain-protein ViaA and its interaction with the AAA+ ATPase RavA, and find that both proteins localise at the inner cell membrane. We demonstrate that RavA and ViaA target specific phospholipids and subsequently identify their lipid-binding sites. We further show that mutations abolishing interaction with lipids restore induced changes in cell membrane morphology and lipid composition. Finally we reveal that these mutations render E. coli gentamicin-resistant under fumarate respiration conditions. Our work thus uncovers a ravA-viaA-based pathway which is mobilised in response to aminoglycosides under anaerobiosis and engaged in cell membrane regulation.

Endoscopy Management of Complete Gastric Outlet Obstruction Secondary to Elipse™ Intragastric Balloon.

The Allurion Elipse™ device is a swallowable balloon in the form of a capsule placed without endoscopy that serves the same purpose as an intragastric balloon (IGB) used for weight loss. We report a case of a 43-year-old female who presented with a complete gastric outlet obstruction confirmed by computed tomography (CT) scan. The patient initially failed conservative management; therefore, the IGB was later removed endoscopically. This is a rare complication and one of the first cases described in the literature; therefore, further studies are needed before its widescale implementation.

A Rare Case of Hemophagocytic Lymphohistiocytosis and Macrophage Activation Syndrome in Settings of Etanercept Use and Epstein-Barr Virus Infection.

Hemophagocytic lymphohistiocytosis (HLH) is a rare syndrome in which widespread activation of the immune system leads to a state of excessive inflammation causing tissue damage. While this condition is mainly established in the pediatric population; due to its rarity, physicians often do not suspect this condition in adults. However, while diagnostic criteria are based on protocols tailored for the pediatric society, recognizing this condition in a timely manner in adults is utterly important to prevent a dismal prognosis. In instances where a concomitant rheumatological disorder is present, the syndrome is referred to as macrophage activation syndrome (MAS). This report describes a case of an adult patient who presented with mucosal bleeding and abdominal pain who was later diagnosed with MAS.

Speaking Softly and Listening Hard: The Process of Involving Young Voices from a Culturally and Linguistically Diverse School in Child Health Research.

The involvement of young people in the planning of research continues to be rare, particularly for young people from culturally and linguistically diverse communities. This paper describes our experience in establishing a Youth Research Advisory Group (YRAG) in South West Sydney (SWS), including barriers and successful strategies. One hundred and fifteen students between school Years 7 and 12 (ages 11-18) took part in at least one of five sessions between 2019 and 2021. In total, we carried out 26 YRAG sessions, with between five and 30 students in each. Sessions focused on mapping the health priorities of the participants and co-developing research project proposals related to their health priorities. Our work with students revealed that their main areas of concern were mental health and stress. This led to material changes in our research strategy, to include "Mental Health" as a new research stream and co-develop new mental health-related projects with the students. Important strategies that enabled our research included maintaining flexibility to work seamlessly with organisational and individual preferences, and ensuring our processes were directed by the schools and-most importantly-the students themselves. Strategies such as maintaining an informal context, responding rapidly to student preference, and regularly renegotiating access enabled us to engage with the students to deepen our understanding of their experiences.

Safety and efficacy of pazopanib as a second-line treatment and beyond for soft tissue sarcomas: A real-life tertiary-center experience in the MENA region.

INTRODUCTION: Sarcomas are uncommon malignancies. No advances have been recently achieved despite multiple efforts. Pazopanib is a safe and effective tyrosine kinase inhibitor used in managing soft tissue sarcomas (STS) after chemotherapy failure. However, its use is limited in developing countries and no efficacy data exist from our region. We aimed to study the efficacy of pazopanib in our population, characterized by response rates of patients with chemotherapy-refractory advanced STS receiving pazopanib. Secondary endpoints included progression-free survival (PFS), overall survival (OS) and toxicity profile. MATERIALS AND METHODS: 15 patients (age≥18 year) diagnosed with advanced STS, refractory to first-line chemotherapy, receiving pazopanib as ≥second-line therapy in one tertiary center in Lebanon were included between January 1st, 2014 and October 31st, 2018. Patient and disease characteristics, disease evaluation, as well as tolerance to treatment, were extracted from charts retrospectively. Statistical analysis was done using SPSS version 24. RESULTS: The mean age was 48.6 [19-66] years. Eleven patients (73.3%) received pazopanib in second-line, whereas four patients (26.7%) received it in third-line. Thirteen patients (86.7%) progressed, and two patients (13.3%) had stable disease. The median PFS was three months [1-19] and the mean OS was 25.4 months [17.2-33.6]. Five patients required dose-reductions due to poor tolerance. CONCLUSION: Conclusions cannot be drawn due to small patient numbers. However, given the 3-month PFS, 13% of patients maintaining stable disease, and tolerable safety profile, it is reasonable to incorporate pazopanib in STS treatment. More focused studies with larger patient populations need to be done in Lebanon.

Diagnostic Performance of FDG-PET/CT Scan as Compared to US-Guided FNA in Prediction of Axillary Lymph Node Involvement in Breast Cancer Patients.

PURPOSE: The aim of this study was to evaluate the diagnostic ability of 2-deoxy-2-[fluorine-18]fluoro-d-glucose (18F-FDG) PET/non-contrast CT compared with those of ultrasound (US)-guided fine needle aspiration (FNA) for axillary lymph node (ALN) staging in breast cancer patients. PATIENTS AND METHODS: Preoperative 18F-FDG PET/non-contrast CT was performed in 268 women with breast cancer, as well as ALN dissection or sentinel lymph node (SLN) biopsy. One hundred sixty-four patients underwent US-guided FNA in combination with 18F-FDG PET/CT. The diagnostic performance of each modality was evaluated using histopathologic assessments as the reference standard. The receiver operating characteristic (ROC) curves were compared to evaluate the diagnostic ability of several imaging modalities. RESULTS: Axillary 18F-FDG uptake was positive in 180 patients, and 125 patients had axillary metastases according to the final pathology obtained by ALN dissection and/or SLN dissection. Of the patients with positive 18F-FDG uptake in the axilla, 21% had false-positive results, whereas 79% were truly positive. Eighty-eight patients had negative 18F-FDG uptake in the axilla, among which 25% were false-negative. 18F-FDG-PET/CT had a sensitivity of 86.59% and a specificity of 63.46% in the assessment of ALN metastasis; on the other hand, US-guided FNA had a sensitivity of 91.67% and a specificity of 87.50%. The mean primary cancer size (p = 0.04) and tumor grade (p = 0.04) in combination were the only factors associated with the accuracy of 18F-FDG PET/CT for detecting metastatic ALNs. CONCLUSION: The diagnostic performance of 18F-FDG PET/CT for the detection of axillary node metastasis in breast cancer patients was not significantly different from that of US-guided FNA. Combining 18F-FDG PET/CT with US-guided FNA or SLN biopsy could improve the diagnostic performance compared to 18F-FDG PET/CT alone.

PTEN R130Q Papillary Tumor of the Pineal Region (PTPR) with Chromosome 10 Loss Successfully Treated with Everolimus: A Case Report.

Papillary tumors of the pineal region (PTPR) can be observed among adults with poor prognosis and high recurrence rates. Standards of therapy involve total surgical excision along with radiation therapy, with no promising prospects for primary adjuvant chemotherapy, as long-term treatment options have not been explored. Chromosome 10 loss is characteristic of PTPR, and PTEN gene alterations are frequently encountered in a wide range of human cancers and may be treated with mTORC1 inhibitors such as everolimus. In parallel, there are no reports of treating PTPR with everolimus alone as a monopharmacotherapy. We report the case of a patient diagnosed with PTPR (grade III) characterized by a PTEN R130Q alteration with chromosome 10 loss that was treated with everolimus pharmacotherapy alone, resulting in an asymptomatic course and tumor regression, a rare yet notable phenomenon not described in the literature so far with potential to alter the management approach to patients with PTPR.

Outcomes of Patients with Malignancy Admitted to the Intensive Care Units: A Prospective Study.

INTRODUCTION: Decisions regarding whether advanced cancer patients should be admitted to the ICU are based on a complex suite of considerations, including short- and long-term prognosis, quality of life, and therapeutic options to treat cancer. We aimed to describe demographic, clinical, and survival data and to identify factors associated with mortality in critically ill advanced cancer patients with nonelective admissions to general ICUs. MATERIALS AND METHODS: Critically ill adult (≥18 years old) cancer patients nonelectively admitted to the intensive care units at the American University of Beirut Medical Center between August 1st 2015 and March 1st 2019 were included. Demographic, clinical, and laboratory data were prospectively collected from the first day of ICU admission up to 30 days after discharge. This study was strictly observational, and clinical decisions were left to the discretion of the ICU team and attending physician. RESULTS: 272 patients were enrolled in the study between August 1st 2015 and March 1st 2019, with an ICU mortality rate of 43.4%, with the number rising to 59% within 30 days of ICU discharge. The mean length of stay in our ICU was 14 days (IQR: 1-120) with a median overall survival of 22 days since the date of ICU admission. The major reasons for unplanned ICU admission were sepsis/septic shock (54%) and respiratory failure (33.1%). Cox regression analysis revealed 7 major predictors of poor prognosis. Direct admission from the ED was associated with a higher risk of mortality (48.9%) than being transferred from the floor (32.6%) (p=0.014). CONCLUSION: Our study has shown that being directly admitted to the ICU from the ED rather than being transferred from regular wards, developing AKI, sepsis, MOF, and ARDS, or having an uncontrolled malignancy are all predictive factors for short-term mortality in critically ill cancer patients nonelectively admitted to the ICU. Vasopressor use and mechanical ventilation were also predictors of mortality.

Correlation of genetic alterations by whole-exome sequencing with clinical outcomes of glioblastoma patients from the Lebanese population.

INTRODUCTION: Glioblastoma (GBM) is an aggressive brain tumor associated with high degree of resistance to treatment. Given its heterogeneity, it is important to understand the molecular landscape of this tumor for the development of more effective therapies. Because of the different genetic profiles of patients with GBM, we sought to identify genetic variants in Lebanese patients with GBM (LEB-GBM) and compare our findings to those in the Cancer Genome Atlas (TCGA). METHODS: We performed whole exome sequencing (WES) to identify somatic variants in a cohort of 60 patient-derived GBM samples. We focused our analysis on 50 commonly mutated GBM candidate genes and compared mutation signatures between our population and publicly available GBM data from TCGA. We also cross-tabulated biological covariates to assess for associations with overall survival, time to recurrence and follow-up duration. RESULTS: We included 60 patient-derived GBM samples from 37 males and 23 females, with age ranging from 3 to 80 years (mean and median age at diagnosis were 51 and 56, respectively). Recurrent tumor formation was present in 94.8% of patients (n = 55/58). After filtering, we identified 360 somatic variants from 60 GBM patient samples. After filtering, we identified 360 somatic variants from 60 GBM patient samples. Most frequently mutated genes in our samples included ATRX, PCDHX11, PTEN, TP53, NF1, EGFR, PIK3CA, and SCN9A. Mutations in NLRP5 were associated with decreased overall survival among the Lebanese GBM cohort (p = 0.002). Mutations in NLRP5 were associated with decreased overall survival among the Lebanese GBM cohort (p = 0.002). EGFR and NF1 mutations were associated with the frontal lobe and temporal lobe in our LEB-GBM cohort, respectively. CONCLUSIONS: Our WES analysis confirmed the similarity in mutation signature of the LEB-GBM population with TCGA cohorts. It showed that 1 out of the 50 commonly GBM candidate gene mutations is associated with decreased overall survival among the Lebanese cohort. This study also highlights the need for studies with larger sample sizes to inform clinicians for better prognostication and management of Lebanese patients with GBM.

Impact of Commercialized Genomic Tests on Adjuvant Treatment Decisions in Early Stage Breast Cancer Patients.

INTRODUCTION: Advances in genomic techniques have been valuable in guiding decisions regarding the treatment of early breast cancer (EBC) patients. These multigene assays include Oncotype DX, Prosigna, and Endopredict. There has generally been a tendency to overtreat or undertreat patients, and having reliable prognostic factors could significantly improve rates of appropriate treatment administration. In this study, we showcase the impact of genomic tests on adjuvant treatment decisions in EBC patients. MATERIALS AND METHODS: This is a retrospective study that includes EBC patients treated between December 2016 and February 2018. The physician's choice of treatment was recorded before and after obtaining the results of the genomics tests. Baseline demographics and pathological data were collected from medical records. RESULTS: A total of 75 patients were included. Fifty patients underwent Oncotype DX genomic analysis, 11 patients underwent Prosigna analysis, and 14 patients underwent Endopredict analysis. A total of 21 physicians' plans (28%) were initially undecided and then carried out after obtaining genomic test results. 13 patients were planned to undergo endocrine therapy alone, while 8 were planned to undergo both endocrine therapy and chemotherapy. Treatment was changed in 26 patients (34.67%). The decision to deescalate therapy was taken in 19 patients (25.33%). The decision to escalate treatment was made in 7 patients (9.33%). CONCLUSION: Our study demonstrates the importance of genomics testing, as it assisted physicians in avoiding unnecessary adjuvant chemotherapy in 25.33% of patients, thus reducing side effects of chemotherapy and the financial burden on patients.

Fertility in Breast Cancer Survivors in the Middle East: A Retrospective Study.

INTRODUCTION: By the time they complete breast cancer therapy, many young patients are still of childbearing age. We aim to estimate the incidence of pregnancies in women who completed treatment and examine the percentage of patients who received fertility counseling before initiation of therapy. MATERIAL AND METHODS: Electronic health records of breast cancer patients between 2008 and 2014 at AUBMC were screened for exclusion criteria of having metastatic disease or known infertility, still receiving therapy, and being above 42 years at diagnosis. Data about therapy and tumor characteristics was obtained for the included survivors who were interviewed as well via telephone for information about fertility preservation counseling, pregnancy occurrence, and delivery. RESULTS: 451 breast cancer patients were identified. 39 patients remained after application of exclusion criteria. 30.76% (n = 12) wanted more children at the time of diagnosis. 10.25% (n = 4) of all 39 patients treated for breast cancer achieved one or more pregnancy after a median time of 3.83 years after completion of therapy. 25% (n = 3) of women who wanted more children at diagnosis (n = 12) were able to conceive. 23.07% (n = 9) of patients discussed fertility with their primary oncologist prior to treatment initiation. 35.89% (n = 14) of patients were aware of fertility preservation technique availability, but none of these patients used one. CONCLUSIONS: The observed rate of pregnancy is comparable to the literature. There is a lack in fertility counseling of breast cancer patients, and the rate of use of fertility preservation techniques is very low despite prior knowledge about their availability.

Demographics and outcomes of meningioma patients treated at a tertiary care center in the Middle East.

OBJECTIVE: Meningioma is the most common intracranial primary brain tumor. Risk factors such as age and exposure to radiation as well as prognostic factors such as grade, location, and extent of surgical resection have been reported in the literature worldwide; however, to our knowledge, data from the Middle East is still warranted. In this study, we aim to identify the characteristics, risk factors and outcomes of meningioma patients treated at a multidisciplinary regional referral center in the Middle East. PATIENTS AND METHODS: This is a retrospective chart review with a prospective follow up of outcomes. It included patients diagnosed with meningioma between January 2005 and December 2015 at the American University of Beirut Medical Center. Patient's demographics, risk factors and outcomes were first retrospectively collected. Then, we conducted phone calls to all included alive patients to update their disease status and outcomes. RESULTS: One-hundred and ninety-five patients were included. 69 % had grade I tumors and around 31 % with grades II and III meningiomas. The means of the overall survival and progression free survival (PFS) were 198 and 126 months, respectively. The residence area (city vs. countryside), occupation, alcohol use, oral contraceptive use, family history of meningioma, previous head trauma, radiation exposure for head/brain imaging, cell phone use, and finally, the tumor Ki-67 protein level did not correlate with the survival outcomes. The meningioma grade and extent of resection were significant predictors of the PFS on the univariate analysis, whereas, in the multivariate analysis only previous radiotherapy was significant in prolonging PFS. CONCLUSION: In our study cohort, that included around 30 % grades II and III tumors, previous radiotherapy use was the only significant prognostic factor for longer PFS in patients diagnosed with meningioma. Future prospective studies should be conducted to evaluate genetic and molecular factors that could possibly be linked to meningioma grade and prognosis in our population of Middle Eastern patients.

Chemogenomic Screen for Imipenem Resistance in Gram-Negative Bacteria.

Carbapenem-resistant Gram-negative bacteria are considered a major threat to global health. Imipenem (IMP) is used as a last line of treatment against these pathogens, but its efficacy is diminished by the emergence of resistance. We applied a whole-genome screen in Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa isolates that were submitted to chemical mutagenesis, selected for IMP resistance, and characterized by next-generation sequencing. A comparative analysis of IMP-resistant clones showed that most of the highly mutated genes shared by the three species encoded proteins involved in transcription or signal transduction. Of these, the rpoD gene was one of the most prevalent and an E. coli strain disrupted for rpoD displayed a 4-fold increase in resistance to IMP. E. coli and K. pneumoniae also specifically shared several mutated genes, most involved in membrane/cell envelope biogenesis, and the contribution in IMP susceptibility was experimentally proven for amidases, transferases, and transglycosidases. P. aeruginosa differed from the two Enterobacteriaceae isolates with two different resistance mechanisms, with one involving mutations in the oprD porin or, alternatively, in two-component systems. Our chemogenomic screen performed with the three species has highlighted shared and species-specific responses to IMP.IMPORTANCE Gram-negative carbapenem-resistant bacteria are a major threat to global health. The use of genome-wide screening approaches to probe for genes or mutations enabling resistance can lead to identification of molecular markers for diagnostics applications. We describe an approach called Mut-Seq that couples chemical mutagenesis and next-generation sequencing for studying resistance to imipenem in the Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa The use of this approach highlighted shared and species-specific responses, and the role in resistance of a number of genes involved in membrane biogenesis, transcription, and signal transduction was functionally validated. Interestingly, some of the genes identified were previously considered promising therapeutic targets. Our genome-wide screen has the potential to be extended outside drug resistance studies and expanded to other organisms.

Penicillin induces alterations in glutamine metabolism in Streptococcus pneumoniae.

Penicillin is a bactericidal antibiotic that inhibits the synthesis of the peptidoglycan by targeting penicillin-binding proteins. This study aimed to assess through transcriptional profiling the stress response of S. pneumoniae strains after exposure to lethal penicillin concentrations to understand further the mode of action of penicillin. Two experimental designs (time-course and dose-response) were used for monitoring the effect of penicillin on the transcriptional profile. The expression of some genes previously shown to be modulated by penicillin was altered, including ciaRH, pstS and clpL. Genes of the glnRA and glnPQ operons were among the most downregulated genes in the three strains. These genes are involved in glutamine synthesis and uptake and LC-MS work confirmed that penicillin treatment increases the intracellular glutamine concentrations. Glutamine conferred a protective role against penicillin when added to the culture medium. Glutamine synthetase encoded by glnA catalyses the transformation of glutamate and ammonium into glutamine and its chemical inhibition by the inhibitor L-methionine sulfoximine is shown to sensitize S. pneumoniae to penicillin, including penicillin-resistant clinical isolates. In summary, a combination of RNA-seq and metabolomics revealed that penicillin interferes with glutamine metabolism suggesting strategies that could eventually be exploited for combination therapy or for reversal of resistance.