The Increased Prevalence of rmpA Gene in Klebsiella pneumoniae Isolates Coharboring blaNDM and blaOXA-48-like Genes

The emergence of carbapenemase-producing Klebsiella pneumoniae poses a substantial risk to public health. It is essential to comprehend the influence of carbapenemase on the virulence characteristics of K. pneumoniae in order to devise successful strategies for combating these infections. In this study, we explored the distribution disparity of virulence determinants between carbapenemase-producing (CP-Kp, n = 52) and carbapenemase-nonproducing (CN-Kp, n = 43) isolates. The presence of carbapenemases was detected via the modified carbapenem inactivation method and confirmed by PCR. The New Delhi metallo-β-lactamase (blaNDM) and Oxacillinase-48-like (blaOXA-48-like) genes were the most prevalent (94.23% and 76.92%, respectively) in CP-Kp isolates. Coexistence of blaNDM and blaOXA-48-like was observed in 71.15% of isolates, whereas 5.77% coharbored blaNDM and blaKPC. PCR analysis revealed the presence of several virulence genes, including adhesins (fimH, 92.63%, mrkD, 97.89%), capsule-associated virulence (uge, 90.53%), the K2 capsule serotype (k2, 6.32%), the iron acquisition system (kfu, 23.16%), and the regulator of mucoid phenotype (rmpA, 28.42%). A significantly higher prevalence of rmpA was detected in the CP-Kp compared with the CN-Kp (24/52 vs. 3/43, p < 0.0001), indicating a potential association between rmpA and carbapenemase acquisition. In addition, the majority of rmpA (22/24) positive isolates in the CP-Kp isolates coharbored blaNDM and either blaOXA-48-like or blaKPC.

Investigating the relationship between carbapenemase production and biofilm formation in Klebsiella pneumoniae clinical isolates

OBJECTIVE

Carbapenemase production and biofilm formation in K. pneumoniae are crucial factors influencing the pathogenicity and antibiotic resistance of this bacterium. This study investigated the interplay between carbapenemase production and biofilm formation in K. pneumoniae clinical isolates.

RESULTS

The distribution of biofilm-forming ability significantly differed between carbapenemase-producing (CP-Kp) (n = 52) isolates and carbapenemase-nonproducing (CN-Kp) isolates (n = 37), suggesting a potential link between carbapenemase production and biofilm formation. All the blaNDM-1-harbouring isolates demonstrated biofilm formation, with varying levels classified as strong (33.33%), moderate (22.22%), or weak (44.45%). blaNDM-1 and blaKPC-coharbouring isolates did not exhibit strong or moderate biofilm formation. blaNDM-1 and blaOXA-48-coharbouring isolates were predominantly moderate (48.65%), followed by weak (32.43%), with none showing strong biofilm production. These findings suggest a correlation between the presence of carbapenemases and biofilm-forming ability; however, the heterogeneity in biofilm-forming abilities associated with different carbapenemase types and the absence of strong biofilm producers in the detected carbapenemase combinations prompt a closer look at the complex regulatory mechanisms governing biofilm formation in CP-Kp isolates.

Posttraumatic hydrocephalus: Recent advances and new therapeutic strategies

Background

Hydrocephalus or ventriculomegaly is a condition brought on by an overabundance of cerebrospinal fluid (CSF) in the ventricular system. The major contributor to posttraumatic hydrocephalus (PTH) is traumatic brain injuries (TBIs), especially in individuals with occupations set in industrial settings. A variety of criteria have been employed for the diagnosis of PTH, including the combination of neurological symptoms like nerve deficits and headache, as well as an initial improvement followed by a worsened relapse of altered consciousness and neurological deterioration, which is detected by computed tomography-brain imaging that reveals gradual ventriculomegaly.

Aim

In this article, we discuss and summarize briefly the current understandings and advancements in the management of PTH.

Methods

The available literature for this review was searched on various bibliographic databases using an individually verified, prespecified approach. The level of evidence of the included studies was considered as per the Centre for Evidence-Based Medicine recommendations.

Results

The commonly practiced current treatment modality involves shunting CSF but is often associated with complications and recurrence. The lack of a definitive management strategy for PTH warrants the utilization of novel and innovative modalities such as stem cell transplantations and antioxidative stress therapies.

Conclusion

One of the worst complications of a TBI is PTH, which has a high morbidity and mortality rate. Even though there hasn't been a successful method in stopping PTH from happening, hemorrhage-derived blood, and its metabolic by-products, like iron, hemoglobin, free radicals, thrombin, and red blood cells, may be potential targets for PTH hindrance and management. Also, using stem cell transplantations in animal models and antioxidative stress therapies in future studies can lower PTH occurrence and improve its outcome. Moreover, the integration of clinical trials and theoretical knowledge should be encouraged in future research projects to establish effective and updated management guidelines for PTH.

Comparative analysis of the ocular surface microbiome in type-1, type-2 diabetes-mellitus and healthy individuals

AIM

Ocular health greatly impacts the quality of life, and diabetes-mellitus (DM) is a major cause of several visual diseases. Likewise, microbiomes have a pivotal role in eye health. The aim was to study the effect of DM, both type-1 (T1DM) and type-2 (T2DM) on the ocular microbiome.

METHODS AND RESULTS

a total of 70 subjects were recruited for this study and divided into 2 main groups: healthy non-diabetic (n = 18) and diabetic (28 T1DM and 24 T2DM). The ocular surface (OS) microbiome was more diverse in the healthy group than in the diabetic one. Taxonomic analysis revealed Proteobacteria as the main phylum (healthy non-diabetic 41.8%, T1DM 50.6%, T2DM 52.5%), besides Streptococcus (healthy non-diabetic 16%, T1DM 26.75%, T2DM 29.20%) and Paracoccus (healthy non-diabetic 17%, T1DM 34.85%, T2DM 37.47%) as the main genera. No significant diversity was found between T1DM and T2DM on both phylum and genus levels; yet genera Brevundimonas and Leptotrichia were more significantly predominant in T1DM.

CONCLUSION

Two pathogenic genera, Streptococcus and Paracoccus, were more predominant in the DM group than in the healthy one.

Blood Proteomics Analysis Reveals Potential Biomarkers and Convergent Dysregulated Pathways in Autism Spectrum Disorder: A Pilot Study

Autism spectrum disorder (ASD) is an umbrella term that encompasses several disabling neurodevelopmental conditions. These conditions are characterized by impaired manifestation in social and communication skills with repetitive and restrictive behaviors or interests. Thus far, there are no approved biomarkers for ASD screening and diagnosis; also, the current diagnosis depends heavily on a physician's assessment and family's awareness of ASD symptoms. Identifying blood proteomic biomarkers and performing deep blood proteome profiling could highlight common underlying dysfunctions between cases of ASD, given its heterogeneous nature, thus laying the foundation for large-scale blood-based biomarker discovery studies. This study measured the expression of 1196 serum proteins using proximity extension assay (PEA) technology. The screened serum samples included ASD cases (n = 91) and healthy controls (n = 30) between 6 and 15 years of age. Our findings revealed 251 differentially expressed proteins between ASD and healthy controls, of which 237 proteins were significantly upregulated and 14 proteins were significantly downregulated. Machine learning analysis identified 15 proteins that could be biomarkers for ASD with an area under the curve (AUC) = 0.876 using support vector machine (SVM). Gene Ontology (GO) analysis of the top differentially expressed proteins (TopDE) and weighted gene co-expression analysis (WGCNA) revealed dysregulation of SNARE vesicular transport and ErbB pathways in ASD cases. Furthermore, correlation analysis showed that proteins from those pathways correlate with ASD severity. Further validation and verification of the identified biomarkers and pathways are warranted.

Biologically-Relevant Staphylococcus Aureus Biofilm Phenotype Characterisation And Liability To Novel Antibiofilm Drugs

Objectives

To characterise the biofilm matrix composition of a newly described Staphylococcus aureus biofilm phenotype.

Method

This experimental study was conducted at the Faculty of Pharmacy, Helwan University, Cairo, Egypt, from January 2021 to March 2022, and comprised methicillin-resistant Staphylococcus aureus and methicillin-susceptible Staphylococcus aureus biofilm-forming clinical isolates which were allowed to construct biofilms under two distinct culture conditions; one a commonly used condition, and the other one a novel, more biologically-relevant condition. The formed biofilms were analysed for matrix composition through treatment with proteinase,sodium meta-periodate, and streptokinase. The efficacy of Cis-2-Decenoic acid and hamamelitannin on the biologically-relevant biofilms was evaluated using biofilm viability assay based on a colorimetric assay for measuring cell metabolic activity and scanning electron microscope imaging. Data was analysed using GraphPad Prism 5.01.

RESULTS

Of the 58 isolates, 45(77.6%) were methicillin-resistant Staphylococcus aureus and 13(22.4%) were methicillin susceptible Staphylococcus aureus. There was significant difference in responses to streptokinase, proteinase and sodium meta-periodate (p<0.05) among the differentially-developed biofilms in methicillin-resistant Staphylococcus aureus isolates. Regarding the methicillin-susceptible Staphylococcus aureus isolates, the differentially-developed biofilms showed significantly different liabilities to streptokinase only (p<0.05). Mean biofilm inhibition for Cis-2- Decenoic acid was 54.27±27.93% and mean biofilm dispersion was 71.92±11.59% while the corresponding valuesfor hamamelitannin were 83.03±13.95% and 70.48±7.116% against the newly described methicillin-resistant Staphylococcus aureus biofilm phenotype.

CONCLUSIONS

Applying biologically-relevant culture conditions on staphylococci biofilms and antibiofilm drugs is recommended.

Atypical Presentations of Foix-Chavany-Marie Syndrome (FCMS) in Stroke

Foix-Chavany-Marie syndrome (FCMS) presents with anarthria and bilateral (B/L) central facio-linguo-velo-pharyngo-masticatory paralysis with "autonomic voluntary dissociation." The most common cause of FCMS is cerebrovascular disease, while rarer causes include central nervous system infection, developmental disorders, epilepsy, and neurodegenerative disorders. Even though this syndrome is also referred to as (B/L) anterior operculum syndrome, patients with lesion in sites other than (B/L) opercular regions also can develop the syndrome. In this article we describe two such atypical cases. Case 1: A 66-year-old man with diabetes and hypertension who is a smoker had right-sided hemiplegia one year back developed the syndrome acutely two days before admission. CT brain showed left perisylvian infarct and right internal capsule anterior limb infarct. Case 2: A 48-year-old gentleman, who is a diabetic and hypertensive had right-sided hemiplegia one year back and developed the syndrome acutely two days before admission. CT brain showed (B/L) infarcts in the posterior limb of the internal capsule. Both patients had bifacial, lingual, and pharyngolaryngeal palsy thereby confirming the diagnosis of FCMS. None of them had the classical (B/L) opercular lesions on imaging and one patient did not even have a unilateral opercular lesion. Contrary to the common teaching, (B/L) opercular lesions are not always necessary to produce FCMS and can occur even without opercular lesions at all.

Antibacterial and Antivirulence Activities of Acetate, Zinc Oxide Nanoparticles, and Vitamin C Against E. coli O157:H7 and P. aeruginosa

Infectious diseases remain one of the major health challenges worldwide due to the problem of antimicrobial resistance. Conventional antimicrobials have the disadvantage that bacteria rapidly acquire resistance to them, so alternatives must be developed to combat antibiotic resistance. Nanotechnology and the repurposing of existing drugs with known biological profiles are new approaches to replacing conventional antimicrobials. In this paper, we have tested the antibacterial activity of sodium acetate (NaA), vitamin C (VC), and zinc oxide nanoparticles (ZnO NPs) against Escherichia coli O157:H7 ATCC 51659 and Pseudomonas aeruginosa ATCC 27853. MIC values for tested compounds ranged from 0.08 to 6.5 mg ml^-1, and the effect of combinations and safety profiles against HepG2 cell line of these compounds were also evaluated. At sub-MIC values, tested compounds had a potential antivirulence effect by inhibiting motility and reducing biofilm formation and maturation. Collectively, ZnO NPs and VC are considered safe alternatives to traditional antibiotics that are capable of reducing the development of antibiotic resistance in microbes. Graphical abstract representing the main aim and the final findings of our work. Spread of multidrug-resistant (MDR) bacterial strains created an urge for alternative safe antimicrobial agents. In this work, we found that ZnO NPs and vitamin C are potential candidates that could be used against MDR E.coli and P. aeruginosa.

Irritable Bowel Syndrome Demographics: A Middle Eastern Multinational Cross-sectional Study

BACKGROUND: Irritable bowel syndrome (IBS) is the most frequent functional gastrointestinal (GI) disorder. In this study, we aimed to evaluate the different aspects of IBS among Middle Eastern residents. METHODS: During the study period, patients attending gastroenterology clinics of nine tertiary referral centers in four Middle Eastern couturiers (Iran, Egypt, Kuwait, and Turkey) were evaluated by Rome IV diagnostic criteria, and those who fulfilled the diagnostic criteria of IBS were asked to fill in a questionnaire covering different demographics and clinical aspects. RESULTS: Overall, during a 6-month period, 509 patients with IBS were included. 41.3% of the participants were male (210 patients), and 37.4% of them had academic education. 50% of the participants were Caucasian, and 34% were Arab, and originally, they were citizens of 18 countries. 77.4% of the participants were residents of subtropical areas, while 22.2% were living in temperate regions. The average age of the participants during the first presentation in subtropical and temperate areas were 38.4 ± 12.19 and 38.06 ± 12.18 years, respectively (P = 0.726). The most common subtypes of IBS in subtropical areas were unclassified (IBS-U, 44.4%), constipation dominant (IBS-C, 27.6%), mixed pattern (IBS-M, 21%), and diarrhea dominant (IBS-D, 6.8%) in descending order while in temperate areas the most common subtypes were IBS-U (43.3%), and IBS-D (22.1%), respectively (P < 0.001). Besides abdominal pain, the most common symptom of patients in each region was bloating (62.2% and 68.1%, respectively, P = 0.246). The rate of depression and anxiety were significantly higher among the residents of temperate areas in comparison with subtropical regions (41.6% vs. 16.5% and 80.5% vs. 58.4%, respectively, P < 0.001). CONCLUSION: Although the average age of IBS presentation is the same in subtropical and temperate areas, it seems that in temperate areas, the rate of IBS-D is more prevalent than in subtropical regions. The rate of anxiety and depression are significantly higher among those who searched social media and the internet to get information about their problems.

Restoring NK cells functionality via cytokine activation enhances cetuximab-mediated NK-cell ADCC: A promising therapeutic tool for HCC patients

Natural Killer (NK) cells are considered the first line of defense against viral infections and tumors. Several factors affect NK cytotoxic activity rendering it dysfunctional and thereby impeding the ability to scavenge abnormal cells as a part of immune escaping mechanisms induced by different types of cancers. NK cells play a crucial role augmenting the activity of various types of anticancer mAb since dysfunctional NK cells are the main reason for the low response to these therapies. To this light, we examined the phenotypic characters of the circulating NK cells isolated from HCC patients compared to healthy controls. Then, dysfunctional NK cells, from HCC patients, were reactivated with cytokines cocktail and their cytotoxic activity with the anti-EGFR mAb "cetuximab" was investigated. This showed a downregulation of patients NK cells activating receptors (NKP30, NKP46, NKG2D and CD16) as well as CD56 and up-regulation of NKG2A inhibitory receptor. We also reported an increase in aberrant CD56^- NK cells subset in peripheral blood of HCC patients compared to healthy controls. Thus, confirming the dysfunctionality of peripheral NK cells isolated from HCC patients. Cytokines re-activation of those NK cells lead to upregulation of NK activating receptors and downregulation of inhibitory receptor. Moreover, the percentage of aberrant CD56^- NK cells subset was reduced. Here, we proved that advanced HCC patients have an increased percentage of more immature and noncytotoxic NK cell subsets in their peripheral blood, which might account for the low cytotoxicity noticed in those patients. A significant improvement in the cytotoxicity against HCC was noticed upon using reactivated NK cells combined with cetuximab. Therefore, this study highlights the potential recruitment of NK immune cells along with cetuximab to enhance cytotoxicity against HCC.

Interrupted crosstalk between natural killer cells and anti-epidermal growth factor receptor: a possible role in hepatocellular carcinoma treatment failure

Hepatocellular carcinoma (HCC) is a major health problem worldwide. Most patients are diagnosed for the first time at late stages; this leads to a very poor prognosis. It is challenging to discover strategies for treatment at these advanced stages. Recently, monoclonal antibodies (mAbs) targeting specific cellular signaling pathways in HCC have been developed. Unfortunately, they still have a low survival rate, and some of them failed clinically to produce effective responses even if they showed very good results against HCC in preclinical studies. This review focuses on and discusses the possible causes for the failure of mAbs, precisely anti-Epidermal Growth Factor Receptor (EGFR) mAb and the crosstalk between this mAb and patients' NK cells.

HilE is required for synergistic activation of SPI-1 gene expression in Salmonella enterica serovar Typhimurium

BACKGROUND

Salmonella enterica serovar Typhimurium is an intestinal pathogen capable of infecting a wide range of animals. It initiates infection by invading intestinal epithelial cells using a type III secretion system encoded within Salmonella pathogenicity island 1 (SPI-1). The SPI-1 genes are regulated by multiple interacting transcription factors. The master regulator is HilD. HilE represses SPI-1 gene expression by binding HilD and preventing it from activating its target promoters. Previous work found that acetate and nutrients synergistically induce SPI-1 gene expression. In the present study, we investigated the role of HilE, nominally a repressor of SPI-1 gene expression, in mediating this response to acetate and nutrients.

RESULTS

HilE is necessary for activation of SPI-1 gene expression by acetate and nutrients. In mutants lacking hilE, acetate and nutrients no longer increase SPI-1 gene expression but rather repress it. This puzzling response is not due to the BarA/SirA two component system, which governs the response to acetate. To identify the mechanism, we profiled gene expression using RNAseq in the wild type and a ΔhilE mutant under different growth conditions. Analysis of these data suggested that the Rcs system, which regulates gene expression in response to envelope stress, is involved. Consistent with this hypothesis, acetate and nutrients were able to induce SPI-1 gene expression in mutants lacking hilE and the Rcs system.

CONCLUSIONS

While the exact mechanism is unknown, these results demonstrate the HilE, nominally a repressor of SPI-1 gene expression, can also function as an activator under the growth conditions investigated. Collectively, these results provide new insights regarding SPI-1 gene regulation and demonstrate that HilE is more complex than initially envisioned.

Evaluation of surgical outcome of giant intracranial meningiomas

Background

The surgery of giant intracranial meningiomas (GIM) is difficult due to its large size, prominent vascularity, including and limiting visualization of various neurovascular structures, and severe cerebral edema. In this study, we will evaluate the surgical outcome of giant meningiomas according to our experience at our hospital in management of giant intracranial meningioma.

Main body

A retrospective analysis of 48 patients with histologically proven meningioma (≥ 6-cm diameter) who underwent surgical treatment at Benha University hospitals over a period of 5 years (June 2014/June 2019) is presented. Details regarding clinical presentation, imaging findings, surgical results and complications, and follow-up status were collected. The study group was composed of 41 females and 7 males. The age of the study group ranged from 38 to 69 years with an average of 49 years. The mean follow-up period was 36 months. Different approaches were used according to tumor location with the aim of gross total removal. Gross total removal was achieved in 90% of cases (43 cases). There were 2 cases with intraoperative complications not related to surgery. Recurrence was present in 4 cases. Mortality in this series was 4% (2 cases) with no reported intraoperative mortality.

Conclusion

Management of giant intracranial meningioma is a relatively common practice in neurosurgical centers in developing countries with the aim of radical total surgical removal being the first and most optimum option. Large size makes surgery difficult, but young age, meticulous surgical techniques, proper localization, trying to minimize operative time, and Simpson grade are of special value. Interdisciplinary cooperation is essential to avoid the common complications like pulmonary embolism (PE), postoperative hematoma in tumor bed that leads to bad surgical outcome.

Analysis of the Correlation Between Antibiotic Resistance Patterns and Virulence Determinants in Pathogenic Klebsiella pneumoniae Isolates from Egypt

Klebsiella pneumoniae is responsible for a plethora of infections involving multiple body systems. This study investigated K. pneumoniae clinical isolates for virulence-associated characters and antibiotic resistance. First, antibiotic sensitivity was determined for 40 K. pneumoniae clinical isolates. Some virulence and resistance-associated factors were studied phenotypically and genotypically. Multiple resistance profiles were observed (multidrug resistant [MDR; 42.5%], extensive drug resistant [XDR; 35%], and pandrug resistant [PDR; 5%]). Moreover, CTX-M-1, TEM, qnrS, and qnrA genes were detected in 70%, 30%, 60%, and 30% of selected isolates, respectively, and 40% of tested isolates were extended-spectrum β-lactamases (ESBLs) producers. Interestingly, all ESBLs producers harbored class 1 integrase gene (IntI1), while 60% of ESBLs producers harbored both CTX-M-1 and TEM. All tested isolates were capsulated while 87.5% were biofilm producers. Fimbriae were detected in 90% of tested isolates (all were biofilm producers and type 3 fimbriae adhesion gene [mrkD] positive). Sequence analysis of OXA-48, qnrS, and IntI1 revealed 100% identity with published sequences, while sequencing of qnrA, OmpK-35, and iron regulatory protein gene (irp2) showed minor variations in the form of one or few single-nucleotide polymorphism. Altogether, the current study revealed that all MDR, XDR, and PDR K. pneumoniae isolates were multivirulent and all harbored 3-5 virulence genes and 2-9 antimicrobial resistance genes and exhibited 8 and 10 different virulence and antimicrobial resistance profiles, respectively. In this study, we also report a positive correlation between some virulence genes and antimicrobial resistance genes among K. pneumoniae tested isolates.

Assessment of the Prevalence of Non-Organ-Specific Autoantibodies in Egyptian Patients with HCV

The relation between non-organ specific autoantibodies (NOSA) and hepatitis C virus (HCV) infection has been investigated within different communities resulting in different prevalence rates and patterns. The purpose of this study was to investigate the prevalence of some NOSA such as RF-IgG, ANA, ASMA, and LKM-1 in Egyptian patients with HCV group as compared with Egyptian healthy controls group. A total of 186 HCV positive serum samples in addition to 81 samples from healthy control were screened for the presence of some common autoantibodies (RF-IgG, ANA, ASMA, and LKM-1) using ELISA technique for ANA, ASMA, and LK-1 while RF-IgG was assayed by latex agglutination technique. The presence of these autoantibodies was tested in relation to some demographic variables and viral titers. Associations were assessed using logistic regression analysis adjusted for potential confounders. Among patients, 100 (53.7%) of 186 and 6 (7.4%) of 81 healthy control group were positive for at least one autoantibody. Furthermore, 2 patients (1%) were positive for three autoantibodies, whereas 22 patients (11.7%) were positive for 2 autoantibodies. The most prevalent autoantibody in anti-HCV-positive group was RF-IgG (87, 46.7%) followed by ASMA (26, 14%). The frequency of autoantibodies was bit higher in women as compared to men. Taken together, this study reports a non-significant difference in prevalence of NOSA between patients with HCV infection and healthy individuals except for ASMA. Likewise, no significant difference was found in prevalence of such autoantibodies when correlated with some demographic variables.

Synergistic action of SPI-1 gene expression in Salmonella enterica serovar typhimurium through transcriptional crosstalk with the flagellar system

BACKGROUND

Salmonella enterica serovar Typhimurium is a common food-borne pathogen. S. enterica uses a type III secretion system encoded within Salmonella pathogenicity island 1 (SPI-1) to invade intestinal epithelial cells. A complex network of interacting transcription factors regulates SPI-1 gene expression. In addition, SPI-1 gene expression is coupled to flagellar gene expression. Both SPI-1 and flagellar gene expression are bistable, with co-existing populations of cells expressing and not expressing these genes. Previous work demonstrated that nutrients could be used to tune the fraction of cells expressing the flagellar genes. In the present study, we tested whether nutrients could also tune the fraction of cells expressing the SPI-1 genes through transcriptional crosstalk with the flagellar genes.

RESULTS

Nutrients alone were not found to induce SPI-1 gene expression. However, when the cells were also grown in the presence of acetate, the concentration of nutrients in the growth medium was able to tune the fraction of cells expressing the SPI-1 genes. During growth in nutrient-poor medium, acetate alone was unable to induce SPI-1 gene expression. These results demonstrate that acetate and nutrients synergistically activate SPI-1 gene expression. The response to acetate was governed by the BarA/SirA two-component system and the response to nutrients was governed by transcriptional crosstalk with the flagella system, specifically through the action of the flagellar regulator FliZ.

CONCLUSIONS

Acetate and nutrients are capable of synergistically activating SPI-1 gene expression. In addition, these signals were found to tune the fraction of cells expressing the SPI-1 genes. The governing mechanism involves transcriptional crosstalk with the flagellar gene network. Collectively, these results further our understanding of SPI-1 gene regulation and provide the basis for future studies investigating this complex regulatory mechanism.

Emergence of Imipenem-Resistant Pseudomonas aeruginosa Clinical Isolates from Egypt Coharboring VIM and IMP Carbapenemases

Pseudomonas aeruginosa is an important human pathogen and the leading cause of nosocomial infections. P. aeruginosa is characterized by massive intrinsic resistance to a multiple classes of antibiotics with carbapenems being the most potent inhibitor of P. aeruginosa and considered the first choice for its treatment. Therefore, it is crucial to investigate novel mechanisms of resistance of P. aeruginosa to carbapenems for achieving successful therapy. A total of 114 P. aeruginosa isolates from two university hospitals in Egypt were recruited in this study. Antimicrobial susceptibility testing revealed that 50 isolates (43.8%) exhibited multidrug-resistant (MDR) phenotype, of them 14 isolates (12.2%) were imipenem (IPM)-resistant. Of these 14 isolates, 13 isolates (11.4%) exhibited the metallo-β-lactamase (MBL) phenotype. MBLs encoding genes, VIM and IMP, were identified by PCR. PCR results revealed that four isolates harbored the VIM gene alone, one isolate harbored IMP gene alone, and four isolates harbored both genes. The correct size of PCR products of VIM and IMP genes (390 and 188 bp, respectively) were sequenced to confirm results of PCR and to look for any possible polymorphism among MBL genes of tested isolates. Data analysis of these sequences showed 100% identity of nucleotide sequences of MBL genes among tested Egyptian patients. To our knowledge, this is the first report of IMP carbapenemase-encoding gene in Africa and the first detection of the emergence of P. aeruginosa coproducing VIM and IMP genes in Egypt.

The Shigella ProU system is required for osmotic tolerance and virulence

To cope with hyperosmotic stress encountered in the environments and in the host, the pathogenic as well as non-pathogenic microbes use diverse transport systems to obtain osmoprotectants. To study the role of Shigella sonnei ProU system in response to hyperosmotic stress and virulence, we constructed deletion and complementation strains of proV and used an RNAi approach to silence the whole ProU operon. We compared the response between wild type and the mutants to the hyperosmotic pressure in vitro, and assessed virulence properties of the mutants using gentamicin protection assay as well as Galleria mellonella moth larvae model. In response to osmotic stress by either NaCl or KCl, S. sonnei highly up-regulates transcription of proVWX genes. Supplementation of betaine greatly elevates the growth of the wild type S. sonnei but not the proV mutants in M9 medium containing 0.2 M NaCl or 0.2 M KCl. The proV mutants are also defective in intracellular growth compared with the wild type. The moth larvae model of G. mellonella shows that either deletion of proV gene or knockdown of proVWX transcripts by RNAi significantly attenuates virulence. ProU system in S. sonnei is required to cope with osmotic stress for survival and multiplication in vitro, and for infection.

Differential effects of c-myc and ABCB1 silencing on reversing drug resistance in HepG2/Dox cells

Multidrug resistance (MDR) in various kinds of cancers represents a true obstacle which hinders the successes of most of current available chemotherapies. ATP-binding cassette (ABC) trasporter proteins have been shown to contribute to the majority of MDR in various types of malignancies. c-myc has recently been reported to participate, at least partly, in MDR to some types of cancers. This study aimed to test whether c-myc could play a role, solely or with coordination with other ABCs, in the resistance of HepG2 cells to doxorubicin (Dox). MDR has been induced in wild-type HepG2 and has been verified both on gene and protein levels. Various assays including efflux assays as well as siRNA targeting ABCB1 and c-myc have been employed to explore the role of both candidate molecules in MDR in HepG2. Results obtained, with regard to ABCB1 silencing on HepG2/Dox cells, have shown that ABCB1-deficient cells exhibited a significant reduction in ABCC1 expression as compared to ABCB1-sufficient cells. However, these cells did not show a significant reduction in other tested ABCs (ABCC5 and ABCC10) while c-myc silencing had no significant effect on any of the studied ABCs. Moreover, silencing of ABCB1 on HepG2 significantly increased fluorescent calcein retention in HepG2 cells as compared to the control cells while downregulation of c-myc did not have any effect on fluorescent calcein retention. Altogether, this work clearly demonstrates that c-myc has no role in MDR of HepG2 to Dox which has been shown to be ABCB1-mediated in a mechanism which might involve ABCC1.

The Multivalent Adhesion Molecule SSO1327 plays a key role in Shigella sonnei pathogenesis

Shigella sonnei is a bacterial pathogen and causative agent of bacillary dysentery. It deploys a type III secretion system to inject effector proteins into host epithelial cells and macrophages, an essential step for tissue invasion and immune evasion. Although the arsenal of bacterial effectors and their cellular targets have been studied extensively, little is known about the prerequisites for deployment of type III secreted proteins during infection. Here, we describe a novel S. sonnei adhesin, SSO1327 which is a multivalent adhesion molecule (MAM) required for invasion of epithelial cells and macrophages and for infection in vivo. The S. sonnei MAM mediates intimate attachment to host cells, which is required for efficient translocation of type III effectors into host cells. SSO1327 is non-redundant to IcsA; its activity is independent of type III secretion. In contrast to the up-regulation of IcsA-dependent and independent attachment and invasion by deoxycholate in Shigella flexneri, deoxycholate negatively regulates IcsA and MAM in S. sonnei resulting in reduction in attachment and invasion and virulence attenuation in vivo. A strain deficient for SSO1327 is avirulent in vivo, but still elicits a host immune response.

Inhibition of quorum sensing-mediated biofilm formation in Pseudomonas aeruginosa by a locally isolated Bacillus cereus

Quorum sensing has been shown to play a crucial role in Pseudomonas aeruginosa pathogenesis where it activates expression of myriad genes that regulate the production of important virulence factors such as biofilm formation. Antagonism of quorum sensing is an excellent target for antimicrobial therapy and represents a novel approach to combat drug resistance. In this study, Chromobacterium violaceum biosensor strain was employed as a fast, sensitive, reliable, and easy to use tool for rapid screening of soil samples for Quorum Sensing Inhibitors (QSI) and the optimal conditions for maximal QSI production were scrutinized. Screening of 127 soil isolates showed that 43 isolates were able to breakdown the HHL signal. Out of the 43 isolates, 38 isolates were able to inhibit the violet color of the biosensor and to form easily detectable zones of color inhibition around their growth. A confirmatory bioassay was carried out after concentrating the putative positive cell-free lysates. Three different isolates that belonged to Bacillus cereus group were shown to have QSI activities and their QSI activities were optimized by changing their culture conditions. Further experiments revealed that the cell-free lysates of these isolates were able to inhibit biofilm formation by P. aeruginosa clinical isolates.

Immunomodulation of RAW 264.7 murine macrophage functions and antioxidant activities of 11 plant extracts

A group of 11 medicinal plants, including Lavandula pubescens, Trigonella foenugricium, Salsola schweinforthi, Calligonum comosum, Silene succulenta, Silene villosa, Bogonvillea glabra, Cakile maritime, Gomphrene celesoids, Mirabilis jalaba, and Silene nocturna growing in Egypt, were extracted and examined for their immunomodulatory and antioxidant activities. RAW 264.7 cells were recruited to investigate the immunomodulatory effect through multiple parameters analysis. First, the proliferation index of macrophages cells was evaluated revealing that Trigonella foenugricium, Silene succulenta and Silene villosa have a significant cytotoxic effect on RAW cells. Interestingly, we observed enhancement of macrophages phagocytic function of by all extracts except Cakile maritime, Gomphrena celosioides and Silene nocturna. Afterwards, macrophages were challenged by incubation with LPS and the effect of various extracts on inflammatory responses was investigated; the generation of NO from activated macrophage was substantially suppressed by 7 extracts namely, Trigonella foenugricium, Calligonum comosum, Silene succulenta, Bougainvillea glabra, Mirabilis jalaba, Gomphrena celosioides and Silene nocturna. TNF-α was decreased by percentage range from 3.8 to 85.8% and Trigonella foenugricium extract showed the highest inhibition of TNF-α release. All extracts except Trigonella foenugricium, Salsola schweinforthi, Silene succulenta and Mirabilis jalaba significantly inhibited COX-2 production from stimulated macrophage. Moreover, evaluating the potential antioxidant activity of these extracts showed that Trigonella foenugricium, Salsola schweinforthi, Calligonum comosum, Bogonvillea glabra and Mirabilis jalaba exhibited some antioxidant activities. Taken together, our results suggest that some of these extracts may have a considerable antinflammatory and antioxidant effects and may be a potential therapeutic choice in the treatment of inflammatory diseases.

Impact of New Chemotherapeutic agents on the outcome of Egyptian patients with Advanced Malignant Pleural Mesothelioma

Patients with malignant pleural mesothelioma (MPM) are well known to have poor response to chemotherapy. Aim of this work was to evaluate the efficacy and safety of new chemotherapeutic agents for the treatment of Egyptian MPM patients.

PATIENTS AND METHODS

The first study was a non-randomized, open-label trial. It included 34 eligible patients who were assigned to receive either cisplatin/ pemetrexed or pemetrexed alone if cisplatin was contraindicated for a maximum of 8 cycles. In the second trial, 21 chemo-naïve patients with histologically proven advanced MPM were included. They received cisplatin and raltitrexed for a maximum of 6 cycles.

RESULTS

In the first trial, the median age was 43.5 years (range 25-69), partial response (PR) was achieved in 37.5%, stable disease (SD) in 50%. Median time to progression (TTP) and overall survival (OS) were 7 and 14 months respectively. Survival at 1 year was 64.7%. No toxicity was observed in 17.6% of patients, grade 3-4 toxicity was evident in 11.8% (neutropenia), 8.8% (anemia), and 2.9% (vomiting and diarrhea). In the second trial, median age was 46 years (range 19- 71), PR was achieved in 23.2%, one complete remission (CR) was reported. SD was noticed in 61.9%. The median TTP and OS were 6 and 12 months respectively. Survival at 1 year was 51.6%.

CONCLUSION

Both cisplatin/pemetrexed and cisplatin/ raltitrexed are effective and safe regimens in the treatment of MPM.

Time to antibiotics and outcomes in cancer patients with febrile neutropenia

BACKGROUND

Febrile neutropenia is an oncologic emergency. The timing of antibiotics administration in patients with febrile neutropenia may result in adverse outcomes. Our study aims to determine time-to- antibiotic administration in patients with febrile neutropenia, and its relationship with length of hospital stay, intensive care unit monitoring, and hospital mortality.

METHODS

The study population was comprised of adult cancer patients with febrile neutropenia who were hospitalized, at a tertiary care hospital, between January 2010 and December 2011. Using Multination Association of Supportive Care in Cancer (MASCC) risk score, the study cohort was divided into high and low risk groups. A multivariate regression analysis was performed to assess relationship between time-to- antibiotic administration and various outcome variables.

RESULTS

One hundred and five eligible patients with median age of 60 years (range: 18-89) and M:F of 43:62 were identified. Thirty-seven (35%) patients were in MASCC high risk group. Median time-to- antibiotic administration was 2.5 hrs (range: 0.03-50) and median length of hospital stay was 6 days (range: 1-57). In the multivariate analysis time-to- antibiotic administration (regression coefficient [RC]: 0.31 days [95% CI: 0.13-0.48]), known source of fever (RC: 4.1 days [95% CI: 0.76-7.5]), and MASCC high risk group (RC: 4 days [95% CI: 1.1-7.0]) were significantly correlated with longer hospital stay. Of 105 patients, 5 (4.7%) died & or required ICU monitoring. In multivariate analysis no variables significantly correlated with mortality or ICU monitoring.

CONCLUSIONS

Our study revealed that delay in antibiotics administration has been associated with a longer hospital stay.

Urinary biomarkers of acute kidney injury in patients with liver cirrhosis

Acute kidney injury (AKI) is a common complication in cirrhotic patients. Serum creatinine is a poor biomarker for detection of renal impairment in cirrhotic patients. This study aimed to evaluate urinary neutrophil gelatinase-associated lipocalin (NGAL) and urinary interleukin-18 (IL-18) as early biomarkers of acute kidney injury in cirrhotic patients. 160 patients with cirrhosis admitted to the Liver Units at Zagazig University Hospitals were classified into three groups: (I) nonascitic patients, (II) ascitic patients without renal impairment, and (III) ascitic patients with renal impairment. Patients with renal impairment were further divided into four subgroups: [A] prerenal azotemia, [B] chronic kidney disease (CKD), [C] hepatorenal syndrome (HRS), and [D] acute tubular necrosis (ATN). Significant elevation of both urinary NGAL and urinary IL-18 in cirrhotic patients with renal impairment especially in patients with ATN was observed. Urinary NGAL and urinary IL-18 have the ability to differentiate between AKI types in patients with cirrhosis. This could improve risk stratification for patients admitted to the hospital with cirrhosis, perhaps leading to early ICU admission, transplant evaluation, and prompt initiation of HRS therapy and early management of AKI.

Are reports of randomized controlled trials improving over time? A systematic review of 284 articles published in high-impact general and specialized medical journals

Background

Inadequate reporting undermines findings of randomized controlled trials (RCTs). This study assessed and compared articles published in high-impact general medical and specialized journals.

Methods

Reports of RCTs published in high-impact general and specialized medical journals were identified through a search of MEDLINE from January to March of 1995, 2000, 2005, and 2010. Articles that provided original data on adult patients diagnosed with chronic conditions were included in the study. Data on trial characteristics, reporting of allocation concealment, quality score, and the presence of a trial flow diagram were extracted independently by two reviewers, and discrepancies were resolved by consensus or independent adjudication. Descriptive statistics were used for quantitative variables. Comparisons between general medical and specialized journals, and trends over time were performed using Chi-square tests.

Results

Reports of 284 trials were analyzed. There was a significantly higher proportion of RCTs published with adequate reporting of allocation concealment (p = 0.003), presentation of a trial flow diagram (p<0.0001) and high quality scores (p = 0.038) over time. Trials published in general medical journals had higher quality scores than those in specialized journals (p = 0.001), reported adequate allocation concealment more often (p = 0.013), and presented a trial flow diagram more often (p<0.001).

Interpretation

We found significant improvements in reporting quality of RCTs published in high-impact factor journals over the last fifteen years. These improvements are likely attributed to concerted international efforts to improve reporting quality such as CONSORT. There is still much room for improvement, especially among specialized journals.

Evaluation and characterisation of A and B fragments of Corynebacterium diphtheriae toxin towards recombinant diphtheria vaccine

BACKGROUND

Diphtheria is a highly communicable disease caused by toxin-producing strains of Corynebacterium diphtheriae.

OBJECTIVES

To evaluate the efficacy of A and B subunits of diphtheria toxin (DT-A, DT-B) as potential vaccines against C. diphtheriae. A culture of C. diphtheriae (strain PW 8) was grown on Loeffler plates while Lingood medium was used for production of diphtheria toxin (DT).

MATERIALS AND METHODS

DT was purified and digested to obtain pure DT-A and DT-B and detoxified to obtain diphtheria toxin. Four groups of mice were immunised with different antigens (Ag) of C. diphtheriae.

RESULTS

The antibody (Ab) titres were significantly increased with immunised groups subsequent to three injections. On the other hand, Ab titres were estimated after the three immunisations and the levels of different Ab isotypes were comparatively measured. The levels of various isotypes immune responses showed variation between immunised groups where the IgG subclasses were significantly increased mainly with DPT immunised group. The IgM and IgA were significantly increased with DT-A more than others. Additionally, the evaluation of the cellular immune responses demonstrated that spleen cells from DPT and DT-A groups gave highly significant proliferative response with production of high levels of IL-2 and IFN-γ (Th1/Th2). Separation and purification of DT gene were performed using polymerase chain reaction (PCR) and sub-cloned in pGEM-T vector, for further studying of recombinant vaccine.

CONCLUSION

Our results showed the possibility to prepare a potent recombinant vaccine containing whole DT gene or DT-A against C. diphtheriae or could be used in treatment of cancer as it give high levels of IL-2 and IFN-γ.

Cytogenetic profile of locally advanced and metastatic Schistosoma-related bladder cancer and response to chemotherapy

Bladder cancer is a common malignancy in developing countries in which bladder infection with the parasite Schistosoma haematobium is prevalent. Several epidemiological, histopathological, and clinical characteristics of schistosoma-associated bladder cancer suggest that it is distinct from bladder cancer seen in other places in the world. The aim of this study was to extend establishing the cytogenetic profile of this type of malignancy in advanced and metastatic cases, and to demonstrate its relation to the end results of systemic therapy. Fluorescence in situ hybridization was applied to interphase nuclei to detect numerical chromosome changes in 41 patients with bladder cancer. Numerical chromosome aberrations were detected in 27 of 41 cases (66%). In 17 (41%) cases, a gain of chromosome 7 was observed, while losses in chromosomes 9 and 17 were detected in 20 (49%) and 18 (44%) cases, respectively. Loss of chromosome Y was detected in 7 of the 32 male patients included in this study (22%). There was a statistically significant association between stage of the disease and overall survival; Bajorin score and time to disease progression and overall survival; and between response to systemic therapy and time to disease progression and overall survival. The only chromosomal abnormality that had a significant relationship with overall survival was the gain of chromosome 4. When the genetic basis of schistosoma-associated bladder cancer is fully understood, new diagnostic and therapeutic strategies could be developed, which in turn may promote better clinical management and survival.

Retagging identifies dendritic cell-specific intercellular adhesion molecule-3 (ICAM3)-grabbing non-integrin (DC-SIGN) protein as a novel receptor for a major allergen from house dust mite

Dendritic cells (DCs) have been shown to play a key role in the initiation and maintenance of immune responses to microbial pathogens as well as to allergens, but the exact mechanisms of their involvement in allergic responses and Th2 cell differentiation have remained elusive. Using retagging, we identified DC-SIGN as a novel receptor involved in the initial recognition and uptake of the major house dust mite and dog allergens Der p 1 and Can f 1, respectively. To confirm this, we used gene silencing to specifically inhibit DC-SIGN expression by DCs followed by allergen uptake studies. Binding and uptake of Der p 1 and Can f 1 allergens was assessed by ELISA and flow cytometry. Intriguingly, our data showed that silencing DC-SIGN on DCs promotes a Th2 phenotype in DC/T cell co-cultures. These findings should lead to better understanding of the molecular basis of allergen-induced Th2 cell polarization and in doing so paves the way for the rational design of novel intervention strategies by targeting allergen receptors on innate immune cells or their carbohydrate counterstructures on allergens.

Recognition of the major cat allergen Fel d 1 through the cysteine-rich domain of the mannose receptor determines its allergenicity

Dendritic cells are professional antigen-presenting cells that are specialized in antigen uptake and presentation. Allergy to cat has increased substantially in recent years and has been shown to be positively associated with asthma. We have recently shown that the mannose receptor (MR), a C-type lectin expressed by dendritic cells, recognizes various glycoallergens from diverse sources and is involved in promoting allergic responses to a major house dust mite allergen in vitro. Here we investigated the potential role of MR in allergic responses to Fel d 1, a major cat allergen. Fel d 1 binding to MR was confirmed by ELISA. Using blocking, gene silencing (siRNA) experiments, and MR knock-out (MR(-/-)) cells, we have demonstrated that MR plays a major role in internalization of Fel d 1 by human and mouse antigen-presenting cells. Intriguingly, unlike other glycoallergens, recognition of Fel d 1 by MR is mediated by the cysteine-rich domain, which correlates with the presence of sulfated carbohydrates in natural Fel d 1. WT and MR(-/-) mice were used to study the role of MR in allergic sensitization to Fel d 1 in vivo. MR(-/-) mice sensitized with cat dander extract and Fel d 1 produced significantly lower levels of total IgE, Fel d 1-specific-IgE and IgG1, the hallmarks of allergic response, compared with WT mice. Our data show for the first time that Fel d 1 is a novel ligand of the cysteine-rich domain of MR and that MR is likely to play a pivotal role in allergic sensitization to airborne allergens in vivo.

The mannose receptor mediates the uptake of diverse native allergens by dendritic cells and determines allergen-induced T cell polarization through modulation of IDO activity

The mannose receptor (MR) is a C-type lectin expressed by dendritic cells (DCs). We have investigated the ability of MR to recognize glycosylated allergens. Using a gene silencing strategy, we have specifically inhibited the expression of MR on human monocyte-derived DCs. We show that MR mediates internalization of diverse allergens from mite (Der p 1 and Der p 2), dog (Can f 1), cockroach (Bla g 2), and peanut (Ara h 1) through their carbohydrate moieties. All of these allergens bind to the C-type lectin-like carbohydrate recognition domains 4-7 of MR. We have also assessed the contribution of MR to T cell polarization after allergen exposure. We show that silencing MR expression on monocyte-derived DCs reverses the Th2 cell polarization bias, driven by Der p 1 allergen exposure, through upregulation of IDO activity. In conclusion, our work demonstrates a major role for MR in glycoallergen recognition and in the development of Th2 responses.

Laminin and fibronectin treatment leads to generation of dendritic cells with superior endocytic capacity

Background

Sampling the microenvironment at sites of microbial exposure by dendritic cells (DC) and their subsequent interaction with T cells in the paracortical area of lymph nodes are key events for initiating immune responses. Most of our knowledge of such events in human is based on in vitro studies performed in the absence of extracellular matrix (ECM) proteins. ECM in basement membranes and interstitial spaces of different tissues, including lymphoid organs, plays an important role in controlling specific cellular functions such as migration, intracellular signalling and differentiation. The aim of this study was, therefore, to investigate the impact of two abundant ECM components, fibronectin and laminin, on the phenotypical and functional properties of DC and how that might influence DC induced T-cell differentiation.

Methodology/Principal Findings

Human monocyte derived DC were treated with laminin and fibronectin for up to 48 hours and their morphology and phenotype was analyzed using scanning electron microscopy, flow cytometry and real time PCR. The endocytic ability of DC was determined using flow cytometry. Furthermore, co-culture of DC and T cells were established and T cell proliferation and cytokine profile was measured using H³-thymidine incorporation and ELISA respectively. Finally, we assessed formation of DC-T cell conjugates using different cell trackers and flow cytometry. Our data show that in the presence of ECM, DC maintain a ‘more immature’ phenotype and express higher levels of key endocytic receptors, and as a result become significantly better endocytic cells, but still fully able to mature in response to stimulation as evidenced by their superior ability to induce antigen-specific T cell differentiation.

Conclusion

These studies underline the importance of including ECM components in in vitro studies investigating DC biology and DC-T cell interaction. Within the context of antigen specific DC induced T cell proliferation, inclusion of ECM proteins could lead to development of more sensitive assays.