Background:
The antimicrobial resistance due to biofilm formation among bacteria is a
significant problem in the healthcare and food industries.
Objective:
The current study describes the synthesis of enrofloxacin derivatives 2-17, and the
evaluation of their anti-bacterial and anti-biofilm activities.
Methods:
Compounds 2-17 were synthesized through the acylation of enrofloxacin with thionyl
chloride, followed by reaction with different aromatic amines. The new analogues identified among
the sixteen compounds were 2-7, 11, 14, and 17.
Results:
Compound 2 appeared to be effective against pathogens S. aureus as well as K. pneumonia,
whereas, compound 11 was found active against K. pneumonia only. Compound 2 inhibited >75%
biofilm formation of S. aureus at 20 μg/mL and K. pneumonia at 10 μg/mL concentrations. These
doses are far below the bactericidal concentration of compound 2, suggesting the anti-virulence
mechanism of these compounds. Compound 11 inhibited 60% biofilm formation of K. pneumoniae
at 70 μg/mL concentration. Compound 5 inhibited the biofilm of K. pneumoniae at 62 μg/mL concentration
but also had bactericidal properties at this concentration. Interestingly, compound 2 eradicated
the preformed biofilm of both the pathogens at much lower doses as compared to control drug,
gentamycin and substrate, enrofloxacin. Cytotoxicity of compounds 2–17 was checked by a standard
method using 3T3 normal cell lines (mouse fibroblast), all compounds were found to be noncytotoxic.
Conclusion:
These compounds can be used alone or with FDA approved drugs to overcome biofilm
related K. pneumoniae and S. aureus infections.
Clinically Approved Drugs Inhibit the Staphylococcus aureus Multidrug NorA Efflux Pump and Reduce Biofilm Formation
