Assessment of chlorine resistant bacteria and their susceptibility to antibiotic from water distribution system in Duhok province

Abstract

Chlorination has been most widely practiced method of disinfection for potable waters since the turn of century and principal means by which the microbial quality of water is maintained in Iraq. Khabur river is the main source of our drinking water in Zahko-Duhok city, here chlorine in form of hypochlorous at concentration 2 ppm are most used. In this paper we have attempted to compare sensitivity of microorganisms toward chlorine and also we have tried to determination of chlorine resistance bacteria to antibiotics. Results from our experiment suggest that bacteria isolated from post chlorinated water samples are more resistant to chlorine disinfection than prechlorinated water samples. the isolated organisms are Staphylococcus aureus, Micrococcus varians and Aeromonas hydrophila fully resistant to chlorine at this concentration and the most resistant bacterium of all isolates is Staphylococci. Although the strains were sensitive to abroad spectrum of antibiotics but the strains show resistant to the most important clinical antibiotics. Suggestion that either the synthesis of unique proteins or aggregation of the bacteria as mechanisms of resistance to inactivation. This study will help us to suggest relevant changes in purification processes for supply of better quality of drinking water to our Municipal Corporation.