Epstein-Barr Virus DNA Enhances Diptericin Expression and Increases Hemocyte Numbers in Drosophila melanogaster via the Immune Deficiency Pathway

Infection with the Epstein-Barr virus (EBV) is associated with several malignancies and autoimmune diseases in humans. The following EBV infection and establishment of latency, recurrences frequently occur resulting in potential viral DNA shedding, which may then trigger the activation of immune pathways. We have previously demonstrated that levels of the pro-inflammatory cytokine IL-17, which is associated with several autoimmune diseases, are increased in response to EBV DNA injection in mice. Whether other pro-inflammatory pathways are induced in EBV DNA pathobiology remains to be investigated. The complexity of mammalian immune systems presents a challenge to studying differential activities of their intricate immune pathways in response to a particular immune stimulus. In this study, we used Drosophila melanogaster to identify innate humoral and cellular immune pathways that are activated in response to EBV DNA. Injection of wild-type adult flies with EBV DNA induced the immune deficiency (IMD) pathway resulting in enhanced expression of the antimicrobial peptide diptericin. Furthermore, EBV DNA increased the number of hemocytes in flies. Conditional silencing of the IMD pathway decreased diptericin expression in addition to curbing of hemocyte proliferation in response to challenge with EBV DNA. Comparatively, upon injecting mice with EBV DNA, we detected enhanced expression of tumor necrosis factor-α (TNFα); this enhancement is rather comparable to IMD pathway activation in flies. This study hence indicates that D. melanogaster could possibly be utilized to identify immune mediators that may also play a role in the response to EBV DNA in higher systems

Phenotypic and Genotypic Characterization of Extended-Spectrum Beta-Lactamases Produced by Escherichia coli Colonizing Pregnant Women

Introduction. Infections caused by extended spectrum beta lactamase (ESBL) producing bacteria continue to be a challenge for choosing the appropriate therapy since they may exhibit coresistance to many other classes of antibiotics. The aim of the study was to screen pregnant women for ESBL producing bacteria in Beirut, Lebanon, to examine their phenotypic and genotypic characterization and to study the association between ESBL colonization with adverse neonatal outcomes. Method. In this cross-sectional study, vaginal samples from 308 pregnant women at 35–37 weeks of gestation were studied during a one-year period. The samples were plated on MacConkey agar and selective MacConkey agar supplemented with ceftazidime. Phenotypic confirmation of ESBL production was performed by double-disc synergy test and all isolates were screened by PCR for the resistance genes blaSHV, blaTEM, and blaCTX-M. Clonal relatedness of Escherichia coli isolates was investigated by pulsed-field gel electrophoresis. Results. In total, 59 women out of 308 (19.1%) were colonized by ESBL producing gram negative bacteria. Two babies born to mothers colonized with ESBL were diagnosed with sepsis. The susceptibility rates of isolates to other antibiotics were 39% to co-trimoxazole, 49.2% to ciprofloxacin, 91.5% to gentamicin, 18.6% to aztreonam and 35.6% to cefepime. Most of isolates were highly sensitive to meropenem and imipenem, with a susceptibility of 93.2%. PCR was performed on all E. coli isolates to detect the most common ESBL producing genes; blaCTX-M was the predominant gene (90.7%), followed by blaTEM (88.4%) and finally blaSHV (44.2%). PFGE analysis of 34 E. coli isolates revealed 22 distinct clusters showing more than 85% similarity. Conclusion. In conclusion, this study showed that Lebanon has a high prevalence of ESBL carriage in pregnant women. Further studies that include a continuous screening of pregnant women and follow up of their newborn clinical status should be conducted to foresee the risk of transmission

Molecular Characteristics of Colistin Resistance in <i>Acinetobacter baumannii</i> and the Activity of Antimicrobial Combination Therapy in a Tertiary Care Medical Center in Lebanon

(1) Background: Infections with pan-drug-resistant (PDR) bacteria, such as A. baumannii, are becoming increasingly common, especially in healthcare facilities. In this study, we selected 15 colistin-resistant clinical A. baumannii isolates from a hospital in Beirut, Lebanon, to test combination therapies and determine their sequence types (STs) and the mechanism of colistin resistance using whole-genome sequencing (WGS). (2) Methods: Antimicrobial susceptibility testing via broth microdilution against 12 antimicrobials from different classes and growth rate assays were performed. A checkerboard assay was conducted on PDR isolates using six different antimicrobials, each in combination with colistin. Genomic DNA was extracted from all isolates and subjected to WGS. (3) Results: All isolates were resistant to all tested antimicrobials with the one exception that was susceptible to gentamicin. Combining colistin with either meropenem, ceftolozane–tazobactam, or teicoplanin showed synergistic activity. Sequencing data revealed that 67% of the isolates belonged to Pasteur ST2 and 33% to ST187. Furthermore, these isolates harbored a number of resistance genes, including blaOXA-23. Mutations in the pmrC gene were behind colistin resistance. (4) Conclusions: With the rise in antimicrobial resistance and the absence of novel antimicrobial production, alternative treatments must be found. The combination therapy results from this study suggest treatment options for PDR ST2 A. baumannii-infected patients