Laboratory and clinical evaluation of ceftriaxone to shigellosis

Abstract

The in vitro study of ceftriaxone was done on 103 strains of Shigella species (3 % of.gr A, 60 % of gr B, 11 % of gr C and 27 % of gr D) obtained from every part of Thailand. The compound showed a very good activity against the test organisms, In the determination of minimal inhibitory concentration (MIC) which was done by agar dilution method, the MIC_50 and MIC_90 obtained were 0.00465 and 0.0262 ug/m1 respectively. In the disc diffusion test for ceftriaxone susceptibility of 30 strains of the organisms, it was found that all of the organisms (100 %) were susceptible and gave the average zone diameter of 30.7 + 3.76 mm (ranges from 17.6 - 40 mm) to the 30 ug ceftriaxone disc. In clinical studies, ceftri¬axone was given intravenously as a single dose of 50 mg/kg body weight to 21 children aged from 1 month to 12 years in both sexes whom were sufferred from shigellosis. The most common causative organisms were S. flexneri (gr B, 62 %) and S. sonnei (gr D 24 %). Most of the patients were clinically cured within 5 days after treatment. Eleven out of thirteen cases (85 %) gave a good temperature response and became afebrile within a mean of 1.08 days (1-2 days), while the reduction of bowel movements to 3 times per day occured in 11 of 19 patients (58 %) within an ayerage of 3.1+1.56 days (1-5 days) after ceftriaxone injection, The stool characteristics of 12 in 19 (63 %) patients became normal. With the well-formed stool after an average of 3.75 + 1.01 days (2-5 days) of treatment, In determination of bacterial stool cultures in these patients, it was found that 11 out of 13 cases (85 %) had bacterial peristance in stools on the fifth day of treatment. The average sera levels assayed micro biologically at 1, 2, 5, 8, 24 and 48 hours after injection were 221 + 39, 156 + 2.3, 118 + 19, 94 + 19, 8 + 4 and 1.7 + 0.04 ug/m1 respectiyely. This suggested that at the 48□(th/) hour after injection, ceftriaxone's con¬centration was still at least 50 times over the MIC_90to Shigella species, So, in shigellosis, ceftriaxone was effective clinically, especially, the very good fever response was achieved but the patients were not bacter-iologically cured.