In-vitro activity of three brands of ceftriaxone against different clinical isolates

Ceftriaxone is an extended spectrum cephalosporin that has been used for decades for combating infections caused by wide array of pathogens and prescription of antibiotic is in favor of specific brands without realizing the potency of the brand. The in-vitro activity of three brands of ceftriaxone and various antibiotics against clinical isolates is studied.

This comparative study was carried in Kathmandu Medical College Teaching Hospital (KMCTH), Basic Science Complex, Duwakot, Bhaktapur in 2009. Thirteen clinical isolates isolated from the specimens processed in the Microbiology Laboratory at KMCTH were used. Minimum inhibitory concentration (MIC) of three brands of ceftriaxone (A, B, and C) was determined by agar dilution and antibiotic resistance patterns were deduced by disc diffusion test.

MIC for three brands of ceftriaxone ranged from < 0.25 to > 256 mg/L. The MIC for brands A and C of ceftriaxone were consistent for all isolates while for brand B, MIC was higher by at least two fold suggesting this brand had less in-vitro activity against isolates tested. All isolates were multi-drug resistant. Ceftriaxone resistant isolates (n = 6) were simultaneously resistant to various antibiotics tested. Imipenem and amino glycosides were sensitive to the isolates studied.

Different brands of ceftriaxone are available in Nepal and imprudent use of less potent antibiotics should be controlled to stop the emergence and spread of multi-drug resistant pathogens and to prevent undue economic burden to the patient and the country.