ABUNDANCE AND ANTIBIOTIC-RESISTANCE OF NON-O1 VIBRIO-CHOLERAE STRAINSIN DOMESTIC WASTE-WATER BEFORE AND AFTER TREATMENT IN STABILIZATION PONDS IN AN ARID REGION (MARRAKESH, MOROCCO)

The abundance and antibiotic resistance of non-O1 Vibrio cholerae stra ins were studied in wastewater before and after treatment in stabiliza tion ponds in an arid Mediterranean climate. The seasonal abundance of non-O1 Vibrio cholerae was the inverse of those of fecal coliforms, w ith high densities in hot periods and low densities in cold periods. A lthough the stabilization pond presents a good efficiency in removing fecal coliforms (97.97%), this treatment system did not produce any si gnificant reduction in non-O1 V. cholerae abundances between the inflo w and outflow stations. Among the 240 non-O1 V. cholerae strains isola ted before and after treatment in the stabilization ponds, 89 (37.1%) isolates were resistant to at least one of 14 tested antibiotics. The levels of antibiotic resistance at the inflow and outflow points of th e system were respectively 40 and 34%, High ampicillin, amoxicillin an d mezlocillin resistance was observed at all sampling points, followed by resistance to cefalexin, cefoperazone and amikacin. Antibiotic res istance can be transferred from non-O1 V. cholerae to other members of the Enterobacteriaceae family such as Escherichia coli K12. Transfer frequencies in nutrient broth and filtered wastewater were 3 x 10(-5) and 2 x 10(-8), respectively.