• ARPITA DUTTA
• SAYANI KUNDU
• ANJALI YADAV
• ARIGHNEE MITRA AND APARAJITA DUTTA
• ARUP KUMAR MITRA

Drinking water from different sources of Kolkata were tested and coliforms were detected from the samples. Two of the samples from the water supply contained way more numbers of organisms than permissible and subjected to characterisation. In the characterisation they were found to be motile, very highly Catalase and Oxidase positive Gram Negetive coliforms which were further tested on EMB agar plates and IMViC test and found out to be Escherichia coli and Enterobacter aerogenes which are both capable of causing enteric diseases. On checking antibiotic susceptibility against commonly prescribed drugs for different enteric diseases such as nalidixic acid, tetracycline, linezolid , clotrimoxazole and cefuroxime by Disc-diffusion method, tetracycline and linezolid had no effect to prevent the growth of the organisms , whereas, the others had very low effect characterised by very small zones of inhibition. Therefore the organisms were distinguished as Multidrug Resistant bacteria (MDR). Next the susceptibility of the organisms against commonly used disinfectants such as alum, chlorine , KMnO4 and camphor was tested by Cup Plate method, Optical density method and Colony Counting Method at different concentrations and it was found that only alum and chlorine had inhibitory effects on the growth of the organisms at quite a high concentration. On doing Fluorescent Microscopy by propidium iodide on the treated samples membrane damage was evidenced characterised by propidium iodide penetrated damaged cells at a very large number. This experiment successfully evidences that even routinely checked samples of water can be source of many pathogenic bacteria. The novel finding of this study is that there is no effect of alum camphor or extracts such as Neem or Tulsi on this kind of MDR bacteria. Only alum and chlorine has the capability of preventing their growth significantly and that also at a very high concentration.

drinking water, coliforms, disinfectants, MDR, inhibition

"Detection of coliforms from drinking water sources, their characterisation and checking their susceptibility against different common drinking water disinfectants", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 4, page no.493-507, April-2019, Available :http://www.jetir.org/papers/JETIR1904786.pdf

"Detection of coliforms from drinking water sources, their characterisation and checking their susceptibility against different common drinking water disinfectants", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 4, page no. pp493-507, April-2019, Available at : http://www.jetir.org/papers/JETIR1904786.pdf