Study demonstrates the impact of 'reverse antibiotic' on gram-negative bacteria Scientists from Skoltech and MSU have investigated antibiotic nybomycin that could prove effective against bacteria resistant to other antibiotics. Their research was published in the journal Antimicrobial Agents and Chemotherapy. All bacterial cells contain topoisomerases, an important group of enzymes that help deal with spatial difficulties stemming from bacterial cell division associated with circular DNA replication. Topoisomerases can be of two types, I and II, depending on breaks they produce in DNA (one strand or double strand). Type II often acts as a target for antibiotics, including fluoroquinolones (FQ), a common group of antibiotics that comprises levofloxacin, ciprofloxacin, and others. Unfortunately, bacteria easily acquire resistance to FQs through mutations in topoisomerase-encoding genes. The emergence of resistant pathogenic strains is a global problem in healthcare, therefore, identifying alternative pathways to thwart their persistence is the current frontier in drug discovery.