DETECTION OF ESCHERICHIA COLI FROM WATER USED IN POULTRY FARMS AT CHITTAGONG

Abstract

An investigation was carried out to assess the microbiological safety level of water used in different poultry farms at Chittagong. All the samples were subjected to Most Probable Number (MPN) determination for observing the bacterial load. Further, culturing and biochemical test were conducted to isolate E. coli from MPN positive samples. Samples were also investigated for the presence of shiga toxin producing genes and antimicrobials sensitivity genes. Total 103 were found positive with MPN index count out of 150 water samples, 35 of them were positive for E. coli. There was a highly significant variation (P value < 0.05) in MPN index count with pH values, water source, geographical locations, farm types and water treatment. Zero coliform count was recorded in only 6% samples with lower pH value (4-5) indicating high bacterial contamination, whereas water with neutral pH values (7-7.5) was found less susceptible to bacterial contamination as 42% samples gave zero coliform count. Though all the water sources were found to be contaminated with bacteria, however, among them, high bacterial contamination was recorded from water samples of drinkers. Total 9 places were included in our study. Of them, samples from Hathazari showed highest zero coliform count (60%), in contrary, rest of the places was almost similar (20-33%) with zero coliform count. Water from broiler and layer farms were highly affected with different coliform bacteria, whereas samples of broiler farms were highly positive (46%) in coliform count (1001 and above). Water treatment with bleaching powder was only practiced in breeder farms. In case of treated water samples, 60%

samples gave zero coliform count indicates lower contamination comparing with non- treatment water. Total 15 (30%) E. coli isolates were collected from Broiler and Layer farms,

whereas lower number was observed in Breeder farms (10%). There was no significant variation (p-value > 0.05) among water sources with E. coli isolation. Molecular detection of all 35 E. coli isolates revealed no evidence of shiga toxin producing genes (stx1, stx2 or both). The E. coli isolates were susceptible to colistin sulphate and gentamicin with an intermediate sensitivity to norfloxacin and doxycyline. The organisms showed 94.29% and 91.43% resistance to ampcillin and tetracycline, respectively. Extensive studies are recommended for the molecular study of different coliform bacteria found in water used in poultry farms and for assessing the effects of the multidrug resistance organisms on poultry population.