The Prevalence of Virulence Factor Genes among Carbapenem-Non-Susceptible Acinetobacter baumannii Clinical Strains and Their Usefulness as Potential Molecular Biomarkers of Infection

Abstract

Healthcare-associated infections caused by multidrug-resistant Acinetobacter baumannii strains are a serious global threat. Therefore, it is important to expand the knowledge on the mechanisms of pathogenicity of these particular bacteria. The aim of this study was to assess the distribution of selected virulence factor genes (bap, surA1, omp33-36, bauA, bauS, and pld) among carbapenem-non-susceptible clinical A. baumannii isolates and to evaluate their potential usefulness as genetic markers for rapid diagnostics of A. baumannii infections. Moreover, we aimed to compare the virulence genes prevalence with the occurrence of carbapenemases genes. A total of 100 carbapenem-non-susceptible A. baumannii clinical isolates were included in the study. The presence of virulence factors and blaOXA genes was evaluated by real-time PCR. The occurrence of virulence factors genes was as follows: 100.0% for the bap and surA1 genes, 99.0% for the basD and pld genes. The bauA and omp33-36 genes were absent among the studied strains. The predominant genes (bap and surA1) are involved in biofilm formation and their presence among all clinical strains can be applied as a genetic marker to recognize A. baumannii infection. High frequencies of the basD gene—involved in siderophore biosynthesis and the gene encoding phospholipase D (pld)—were also noted among blaOXA-positive strains, showing their potential role in a pathogenicity of blaOXA-positive A. baumannii clinical strains.

Virulence Molecular Epidemiology of Clinical Carbapenem-Resistant Acinetobacter baumannii: First Report from Jordan

“…It enhances the persistence of A. baumannii in the hospital environment, and promotes antibiotic resistance and tolerance to other inhibitors [12,13] Surface antigen protein surA1 Surface antigen protein is a periplasmic chaperone protein necessary for cellular invasion. Iron acquisition system BasD Iron acquisition system is essential for bacterial survival and growth in a host under iron-limited conditions [14] Phospholipase D Pld Phospholipase D enhances A. baumannii ability to thrive in serum and invade epithelial cells [15] Outer membrane protein A OmpA Outer membrane protein A (OmpA) is an adhesion protein enhances bacterial attachment to eukaryotic epithelial cells and formation of biofilms [16]…”