Background: Ceftriaxone belongs to the third-generation β-lactam antibiotics
and it is useful for the treatment of a number of infectious diseases caused by both aerobic
and anaerobic Gram-positive and Gram-negative bacteria. Phenylalanine is an essential
aromatic amino acid of human being, from which dopamine and norepinephrine neurotransmitters
are being synthesized. In the present study, we examined their combined efficacy
against different types of pathogenic bacterial strains.
Objective: The aim of the study was designed to investigate the effects of ceftriaxone
combination with phenylalanine on antimicrobial activity
Method: Gram positive-bacteria and Gram negative- including Klebsiella pneumoniae, –
ATCC 25923, Proteus vulgaris, Escherichia coli, Serratia marcrescens, Staphylococcus
epidermis, Alpha haemolyticus streptococcus, Enterococcus faecium, Pseudomonas aeruginosa,
Listeria monocytogenes ATCC 7644, Enterococcus durans, Salmonella kentucky,
Enterobacter aerogenes ATCC 13048 and Candida albicans ATCC 26555 were exposed
to ceftriaxone and phenylalanine based on disk-diffusion method, and Minimum inhibition
concentration (MIC) was determined with ceftriaxone.
Results: 0.3 mol/L ceftriaxone and 0.3 mol/L phenylalanine solutions were mixed and
observed greater zone of inhibition than ceftriaxone or phenylalanine alone against above
mentioned bacterial strains. These results might open up a new avenue for using phenylalanine
in combination with ceftriaxone to lower MIC level for better antibacterial effect,
to reduce side effects of antibiotics, and to reduce emerging threats of antibiotic resistance
Conclusion: In this study, combined use of phenylalanine and ceftriaxone has revealed
increased antimicrobial sensitivity against some selected both Gram positive and Gram
negative bacteria in vitro.