Microbiologists Investigate How to Fight Opportunistic Pathogens

Opportunistic microbes are dangerous to individuals with weakened immune system. Photo courtesy of Inna Basyrova

The Department of Microbiology at Kazan Federal University is investigating factors which allow bacteria to persist in human body when exposed to high-strength antibiotics. The team is focused on Proteus, Morganella, Providencia, and Serratia genera, which all are identified as opportunistic microbes and thus are dangerous to individuals with weakened immune system.

Associate professor Ayslu Mardanova explains, "The list of virulence factors helping microorganisms to survive in a human body, confront with defense mechanisms, and develop resistance against antibiotics, is very long. We are studying the role of hydrolytic enzymes that serve as catalysts for the breakdown of proteins, carbohydrates, and fats. The primary interest are the factors influencing bacteria's invasiveness, the ability of a pathogen to invade tissue, and the creation of biofilms serving as protective barriers and significantly inhibiting the efficiency of antibiotic therapy."

It should be noted, that until recently many opportunistic enterobacteria, including Morganella and Serratia, were not considered dangerous. They were classified as members of the normal gut flora. Now, however, it is evident that Morganella can cause not only cystitis, pyelonephritis, and dysbacteriosis, but also more severe diseases like meningitis, septicemia, and endocarditis.

Serratia can cause bone diseases, eye infections, and pneumonia. Proteus and Providencia contribute to intestinal infections, urinary tract and kidney diseases. They constitute a danger for the patients whose therapy is performed using catheterization.

At this time, researchers have discovered the correlation between the invasiveness of enterobacteria and their ability to synthesize certain enzymes called metalloproteinase. This ability of Proteobacteria increases the level of toxic effects of pathogenic bacteria on human tissues.

A full sequence analysis of Serratia grimesii's genome determined the genes contributing to antibiotic resistance, especially towards beta-lactam drugs. A similar enzyme was found in Morganella.

The results of this research have been already published in Genome Announcements, Microbiology, Bioorganic Chemistry, and Proceedings of the Russian Academy of Sciences.

Source: Kazan Federal University