In-Vitro Susceptibility of Drug Resistant Salmonella Typhi to

Multidrug-resistant typhoid fever (MDRTF) is an important problem in many developing countries and is an emerging problem in the developed world. The existence of MDRTF poses a serious clinical dilemma specifically in the selection of empiric antimicrobial therapy. This paper examines the in vitro susceptibility of drug-resistant and "sensitive " Salmonella typhi isolates from Metro Manila, Philippines using the disc diffusion method (National Committee for Clinical Laboratory Standards) against a new third generation oral cephalosporin, ceftibuten (Cedax). The antimicrobial susceptibility discs used in this investigation were ampicillin (I0 micrograms), chloramphenicol (30 micrograms), trimethoprim-sulfamethoxazole (1.2S/23.75 micrograms), tetracycline (30 micrograms), and ceftibuten (30 micrograms). 168 "sensitive and 78 MDR clinical isolates of S. typhi were analyzed. 98.8 % of the “sensitive" isoates and 96.2 % of the MDR isolates were sensitive to ceftibuten whereas 1.2 % of the " were “sensitive ” isolates and 3.8 % of the MDR isolates were moderately sensitive. There were no isolates resistant to ceftibuten for both groups. Overall, ceftibuten showed very good in vitro activity against MDRTF isolates from Manila. It is recommended that quantitative antimicrobial susceptibility tests (i.e. minimum inhibitory concentration) be performed on MDR as well as the “sensitive ” isolates to confirm their disc diffusion results. [Phil J Microbiol Infect Dis 1995