[abstract] ANTIBIOTIC SENSITIVITY OF BACTERIA ISOLATED FROM THE AQUATIC ENVIRONMENT: IMPLICATIONS FOR CLINICAL THERAPY.

Abstract

Ocean water and tissue samples were obtained from a variety of sources with phylogenetic (shark, fire coral, sea urchin) and geographic (California, Egypt) disparity. These were cultured in Heart infusion, Brucella, Cohunbia, TCBS, Middlebrook 7H1O and 7Hll, and Sabouraud agars, as well as Lowenstein Jensen nedium. Agars were prepared in either distilled water or from ocean water. Plates were incubated in air at room temperature. After isolation of purified colonies, identification procedures were performed. 1SI slants and oxidation/ fermentation tubes were inoculated, and the following tests were performed: growth on TCBS and MacConkey agar; growth on trypticase soy blood agar without sea water; nitrate reduction; 0/129 sensitivity; luminescence; Thornley's arginine; lysine and ornithine decarboxylase; growth at 42 degrees C.; growth in 0,3,6,8 and 10'/0 NaCl; V-P reaction; gas from glucose; acid production from L-arabinose, m-inositol, D-mannose, and sucrose; production of amylase, gelatinase, and lipase. Thirty-three isolates of Vibrio species (including V. harveyi, V. pelagius I and II, V. anguillarum, V. algioolyticus, V. damsela and V. fluvialis II), 2 isolates of Pbotobacteriurn angpstum, and 23 isolates of non-fermentative marine bacteria were identified and characterized. Three gram positive isolates were also isolated. Antibiotic susceptibility testing using 21 different ant~crobials was carried out in rrdcrotiter plates containing antibiotics in Mueller-Hinton broth containing 2.~k NaCl. Analysis of the antibiograms showed that "while the non-fermentative marine bacteria were generally susceptible to the antibiotics tested, marine Vibrio species tended to be relatively resistant to a wide variety of antirrdcrobials, including 1st, 2nd, and 3rd generation cephalosporins. Antibiotics effective against all species included chlorarrphenicol, trirrethoprirn/sulfarrethoxazole, and thienamycin. Other antibiotics which were effective (i.e., only one isolate was resistant) included tetracyline, azthreonam, cefoperazone, and ceftazidirre. Some isolates failed to grow in the medium used for susceptibility testing. Commercial test kits do not yield accurate identifications of bacteria, the acquisition of antimicrobial susceptibility data on these organisms gains added importance.