Antibiotic susceptibility and factors involved in virulence and persistence of Acinetobacter baumannii strains

Abstract

Background: Acinetobacter baumannii has emerged as a medically important pathogen because of the increasing number of infections produced by this organism over the preceding three decades and the global spread of strains with resistance to multiple antibiotic classes. Recently, a particular attention has been drawn to the study of the microbial persistence properties and their correlation with the rate of elimination from the source of infection, as well as the prognosis of the disease progression.

Material and methods: There were examined 53 strains of A. baumannii, isolated from patients with trophic ulcers. The bacteriological examination, as well as tests on determining both the persistence factors and the antibiotic susceptibility of the isolated strains were carried out according to the current method.

Results: A. baumannii strains were highly resistant to all antibiotics tested, 38 (71.7%) showed multidrugresistance. The studies regarding the persistence factors of A. baumannii strains,  revealed that 100%  exhibited an antilysosyme activity, 78.0% – anticomplementary activity, 73.6% – produce biofilms, 58.5% – hemolytic activity, 28.3% and 13.2% – lecithinase and plasma coagulation activity, respectively.

Conclusions: Isolated strains showed higher level of antimicrobial resistance and multiple persistence factors. The study results proved that treatment of trophic ulcers is still a major problem, requiring rational monitoring and management strategies.