title: Investigation of the Virulence Factors and Molecular Characterization of the Clonal Relations of Multidrug-ResistantAcinetobacter baumanniiIsolates.
abstract: Multidrug-resistant (MDR) Acinetobacter baumannii infections are a great public health concern and demand continuous surveillance and antibiotic stewardship. Virulence traits and the pathogenicity of Acinetobacter are less studied compared with the molecular epidemiological and antibiotic resistance profile of this organism. In our present study, we investigated the primary characteristics contributing to the virulence of MDR A. baumannii isolates and compared them with avirulent isolates. A total of 32 well-characterized MDR A. baumannii clinical isolates and 22 avirulent isolates from a healthy individual were subjected to multilocus sequence typing and polymerase chain reaction (PCR) for a variety of biofilm-associated genes. Additionally, a number of in vitro tests were performed to determine virulence properties. Isolates were found to relate to six sequence types (STs) in which the dominant sequence was ST557 in clinical isolates, followed by ST195 and ST208. However, ST557 and ST222 were absent in avirulent isolates. All STs belonged to clonal complex 2 and clonal lineage 2, which is considered to be a universal clone. PCR analysis showed that most clinical isolates were positive for biofilm-forming genes, such as csu and bap, and also carried pga and ompA genes, which were less common in avirulent isolates. Biofilm formation, phospholipase C production, hemolytic activity, and acinetobactin production occurred significantly more frequently in clinical isolates compared with avirulent isolates. Though A. baumannii clonal lineages showed common virulence traits, they differed in virulent phenotype expression. These findings further support previous studies indicating that A. baumannii is a versatile pathogen with an ability to acquire iron and survive in iron-limiting conditions, highlighting the acinetobactin-mediated iron acquisition mechanisms involved in the pathogenesis of A. baumannii infections.
authors.affiliation: King Saud University, College of Science, Department of Botany and Microbiology, PO Box 2455, Riyadh 11451, Saudi Arabia.
authors.forename: Hayssam M
authors.initials: HM
authors.lastname: Ali
authors.affiliation: Alexandria University, Faculty of Agriculture (EL-Shatby), Department of Forestry and Wood Technology, Alexandria, Egypt.
authors.forename: Mohamed Z M
authors.initials: MZM
authors.lastname: Salem
authors.affiliation: Plant Protection Department Faculty of Agriculture Alexandria University, Egypt.
authors.forename: Mohamed S
authors.initials: MS
authors.lastname: El-Shikh
authors.affiliation: Plant Protection Department Faculty of Agriculture Alexandria University, Egypt.
authors.forename: Ahmed Abdel
authors.initials: AA
authors.lastname: Megeed
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
authors.forename: Yahya A
authors.initials: YA
authors.lastname: Alogaibi
authors.affiliation: Riyadh Colleges of Dentistry and Pharmacy, Riyadh, Saudi Arabia.
authors.forename: Ibrahim Ahmed
authors.initials: IA
authors.lastname: Talea
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000145:classification / Q000235:genetics*; D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D009821:Oils; D010636:Phenols; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D009821:Oils; C027222:P & S Liquid; D010636:Phenols; D037521:Virulence Factors