Occurrence and Antibiotic Resistance ofPseudomonas aeruginosaand Faecal Indicator Bacteria: Risk Assessment for Groundwater Supplies (Marrakesh, Morocco)

The dynamic and antibiotic resistance of faecal coliforms, faecal streptococci and Pseudomonas aeruginosa , isolated by standard membrane filtration methods from suburban and rural untreated groundwater supplies, were scrutinized in this study. The annual average densities of these bacteria were respectively 1891 colony forming units (c.f.u.)/100 mL, 1246 c.f.u./100 mL and 206 c.f.u./100 mL. The total occurrence of faecal coliforms and faecal streptococci during the period of study was 94%. Detectable P. aeruginosa was present in 88% of samples. A total of 320 faecal coliforms, 338 faecal streptococci and 208 P. aeruginosa strains, were examined for their resistance to eighteen antibiotics. The overall resistance (resistance to at least one antibiotic) of these bacteria was 100%. The multiresistance (resistance to at least two antibiotics) of faecal coliforms and faecal streptococci was 94%, whereas 100% of P. aeruginosa strains were multiresistant. The monoresistance (resistance to one antibiotic) of fae...