Identification of a novel cassette array in integron-bearing Helicobacter pylori strains isolated from Iranian patients

Helicobacter pylori as the second most common cause of gastric cancer in the world infects approximately half of the developed countries population and 80 of the population living in developing countries. Integrons as genetic reservoirs play major roles in dissemination of antimicrobial resistance genes. To the best of our knowledge, this is the first study to report carriage of class 1 and 2 integrons and associated gene cassettes in H. pylori isolates from Iran. This cross-sectional study was conducted in Tehran among 110 patients with H. pylori infection. Antimicrobial susceptibility testing (AST) for H. pylori strains were assessed by the micro broth dilution method. Class 1 and 2 integrons were detected using PCR. In order to determine gene cassettes, amplified fragments were subjected to DNA sequencing of both amplicon strands. The prevalence of resistance to clarithromycin, metronidazole, clarithromycin, tetracycline, amoxicillin, rifampin, and levofloxacin were 68.2 (n=75), 25.5 (n=28), 24.5 (n=27), 19.1 (n=21), 18.2 (n=20) and 16.4 (n=18), respectively. Frequency of multidrug resistance among H. pylori isolates was 12.7. Class 2 integron was detected in 50 (45.5) and class 1 integron in 10 (9.1) H. pylori isolates. The most predominant gene cassette arrays in class 2 integronbearing H. pylori were included sat-era-aadA1, dfrA1-sat2-aadA1, blaoxa2 and, aadB whereas common gene cassette arrays in class 1 integron were aadB-aadA1-cmlA6, aacA4, blaoxa2, and catB3. The high frequency of class 2 integron and multidrug resistance in the present study should be considered as a warning for clinicians that continuous surveillance is necessary to prevent the further spread of resistant isolates

The total graph of a module with respect to multiplicative-prime subsets

Let M be a module over a commutative ring R and U a nonempty proper subset of M. In this paper, a generalization of the total graph T(Γ(M)), denoted by T(Γ_U (M)) is presented, where U is a multiplicative prime subset of M. It is the graph with all elements of M as vertices, and for two distinct elements m, n ∈ M, the vertices m and n are adjacent if and only if m + n ∈ U. The main purpose of this paper is to extend the definitions and properties given in [1] and [10] to a more general case

Improving protein glycan coupling technology (PGCT) for glycoconjugate vaccine production.

INTRODUCTION: Vaccines are one of the great success stories of modern medicine and an increasingly important strategy in the fight against antimicrobial resistance. Glycoconjugate vaccines, consisting of a protein component covalently linked to a glycan antigen, are extremely efficacious in preventing infectious disease. However, glycoconjugates have yet to reach their full potential, with currently licensed glycoconjugate vaccines available against only four pathogens. Protein glycan coupling technology, where glycoconjugates are biologically produced in purpose engineered bacterial cells, has the potential to revolutionize the field by lowering manufacturing cost and increasing flexibility for tailor-made vaccines. AREAS COVERED: This review gives an overview of the past 20 years of PGCT research, discusses the key developments and current status of the technology, and speculates on the future of PGCT-based vaccinology. EXPERT OPINION: PCGT has the potential to overcome some of the limitations of chemical conjugation production methods. The technology has undergone significant development since its inception, and new discoveries are continually driving the field forward. Vaccines currently in clinical trials have demonstrated the potential of the PGCT to deliver effective glycoconjugate vaccines for unmet medical needs