Monitoramento da qualidade bacteriológica das águas do Riacho Maceió, Fortaleza-CE : susceptibilidade antimicrobiana de cepas de Escherichia coli isoladas de suas águas

Abstract

This research aimed to bacteriological quality monitoring of waters of Maceió stream in Fortaleza city, Ceará State, and the study of antimicrobial susceptibility of Escherichia coli strains isolated from its waters. Ten collections were conducted from April to June 2011 generating a total of 10 samples of water during rain and drought periods. The method used to assess water quality was the most probable number (MPN) of E. coli. We evaluated the physical and chemical parameters (temperature, salinity and pH) where the salinity ranged from 0.2 (minimum) to 10 %0 (maximum), the temperature fluctuated between 26 DC and 30 DC,and the values of pH was between 7.1 and 7.7. The MPN of E. coli from water samples ranged from 1.1 x 103 to > 1600 /100 mL. One hundred- fifieen suspects strains of E. coli were isolated, which forty-three (37.39%) were confirmed. After identifying, the strains were tested with antibiotic-resistant and were subjected to the technique of "curing" of the plasmid by curing agent acridine orange. Thirty-seven (86.1 %) of 43 strains tested showed resistance to at least one antimicrobial tested and only six (13.9%) showed sensitivity to all drugs. All strains were sensitive to gentamicin and meropenem. The rate of multidrug resistance to antimicrobial agents (MAR) was calculated for twenty-four characterized as multidrugresistant strains with MAR > 0.2. After the curing technique, most of the resistance was proved to be of plasmid origino E. coli strains isolated from water samples collected in Maceió stream showed a high degree of antimicrobial resistance that can facilitate the spread of resistant genes between bacterial populations in this environrnent.