[A new rapid antibiotic susceptibility test for enteric bacteria using a color change method]

The rapid antibiotic susceptibility tests that have been developed so far cannot be used in daily work, because of their many difficulties and disadvantages. We have developed a new antibiotic susceptibility test for enteric bacteria which gives the result in 4 hours, easy to perform and inexpensive. This method depends upon the mechanism which detects the acid formed by the bacteria, by the change of the color of the pH indicator in the medium. The susceptibility of 110 different isolates of enteric bacteria (E. coli, Klebsiella, Salmonella, Shigella, Proteus, Enterobacter) to ampicillin, amikacin, trimethoprim-sulfamethoxazole, cephradine, cefazolin, erythromycin, gentamicin, and ofloxacin is examined by this new "Rapid Color Change Test" and disc diffusion method. For most organisms tested, there was a good correlation between the results of the two methods. The overall agreement is found to be 91.43%.