Alzheimer's disease causes memory loss and dementia in older adults through a neurodegenerative mechanism. Despite the pathophysiological clarification of this cognitive disorder, novel molecular and cellular pathways should be identified to determine its exact mechanism. Alzheimer's disease (AD) is pathologically characterized by senile plaques comprising beta‐amyloid and neurofibrillary tangles (NFTs) formed by hyperphosphorylated tau as a microtubule‐associated protein with a key role in the pathogenesis of AD. Periodontitis through inflammatory pathways is a risk factor for deteriorating cognitive impairment in AD patients. Poor oral hygiene coupled with immunocompromised status in older adults causes periodontal diseases and chronic inflammations through an oral bacterial imbalance. Toxic bacterial products, including bacteria themselves, can reach the central nervous system through the bloodstream and evoke inflammatory responses. The present review was conducted to investigate relationships between AD and periodontitis‐involved bacteria as a risk factor.

Background: Acinetobacter baumannii is a global concern that causes healthcare-associated infections due to multidrug resistance against commercially available antimicrobial agents. Objectives: The present study was conducted to determine the antimicrobial susceptibility of A. baumannii isolates from clinical specimens in Shiraz, Iran. In addition, the possible relationship of susceptibility patterns with the presence of integrons and related gene cassettes is investigated. Methods: A. baumannii isolates were collected, and their susceptibility to various antibiotics was tested using the Kirby-Bauer disk diffusion method. Moreover, molecular analyses were performed to detect the presence of the OXA-51-like gene, as well as class I, II, and III integrons, and associated gene cassettes. Results: The majority of isolates were resistant to imipenem (99.4%), piperacillin (98.2%), gentamycin (98.2%), meropenem (97.7%), ceftazidime (95.4%), amikacin (95.4%), and trimethoprim-sulfamethoxazole (90.8%). All strains showed multidrug resistance to the tested antibiotics. The distribution analysis of integrons genes revealed that 90.2, 72.4, and 12.1% of the isolates carried intI1, intI2, and intI3 genes, respectively. Moreover, two types of prevalent gene cassettes, including aad and dfr, were detected in class 1 integron-carrying strains. Conclusions: The current study showed the high prevalence of A. baumannii isolates harboring integrons in our investigated medical center, which may indicate the distribution of multidrug resistance events. The different gene cassette arrays in the present study highlight the remarkable role of geographical issues in disseminating multidrug-resistant isolates. This could be attributed to distinct therapeutic interventions in different areas. The results demonstrate the necessity of continuous surveillance to prevent the distribution of multidrug resistance among A. baumannii strains in Iran.

Background Acinetobacter baumannii is a global concern to cause the health-care-associated infections, due to multidrug resistance against available commercially antimicrobial agents. Regarding this, the present study was conducted to determine the antimicrobial susceptibility of A.baumannii isolates from clinical specimens in Shiraz, and explore the possible relationship of susceptibility patterns with the presence of integrons and related gene cassettes. Methods A.baumannii isolates were collected, and their susceptibility to various antibiotics was tested using Kirby-Bauer disk diffusion method. Also, molecular analyses were performed to detect the presence of OXA-51 like gene, class I, II and III integrons, and associated gene cassettes. Results Majority of isolates demonstrated resistance to imipenem(99.4%),piperacilin(98.2%),gentamycin (98.2%) meropenem (97.7%)ceftazidime(95.4%)amikacin(95.4%) and trimethoprim-sulfamethoxazole (90.8%). All strains showed multidrug-resistance to most of the tested antibiotics. The distribution analysis of integrons genes showed that 90.2%, 72.4% and 12.1% of isolates carried the intI 1, intI2 and intI3 genes, respectively. Moreover, two types of prevalent gene cassettes including aad and dfr were detected in Class 1 integron-carrying strains. Conclusions The current study showed the high prevalence of A.baumannii isolates harboring integrons in our investigated medical center, which may propel distribution of multidrug resistance event. The different types of gene cassette arrays in the present study spotlight the remarkable role of geographical issues in MDR isolates dissemination. This subject could attribute to choose appropriate therapeutic interventions in different areas. Obtained data highlighted the necessity for continuous surveillance to prevent distribution of multidrug resistance among A.baumannii strains in Iran.