Abstract
The ground and surface water obtained from various
sources such as tap, tubewell, pond, river and sea were
studied in three different seasons: summer, rainy and
winter, for the evidence of fecal pollution. A total number
of 690 samples were bacteriologically examined for the
determination of total coliforms, fecal coliforms, total
bacterial count and presence of Escherichia coli, fecal
streptococcі, Salmonella typhimurium, Salmonella paratyphi,
Shigella dysenteriae, Shigella flexneri and Shigella sonnei.
The physico-chemical factors of water samples and their
influence on water quality were analysed. The bacterial
isolates of water were tested for their sensitivity to seven
antibiotics, Ten selected isolates were further studied for
plasmid determination.
The level of pollution with MPN of total coliforms
ranged from 0 to 2400, fecal coliforms 0 to 920 and total
bacterial count (log10) 1.17 to 7.98 per 100 ml of water
samples of different sources. The degree of pollution was
the highest in river water and the lowest in tubewell water.
The counts were significantly (P<0.05) different from each
other except in tap and tubewell water. Results indicated
that densities of fecal pollution in pond and river water
were markedly influenced by seasonal variation (summer,
rainy and winter) but such influence there was no of seasonin tubewell and tap water. Pollution was higher during
summer and winter than rainy season, but the degree of
contamination was remarkably high in river water during
rainy season. Out of the total 690 samples examined, 58 per
cent were found positive for fecal streptococci, 77 per cent
E. coli, 35 per cent Sal. typhimurium, 30 per cent Sal.
paratyphi and 101 per cent Shigella, of which 40 per cent
were Shigella dysenteriae, 28 per cent Shigella flexneri and
30 per cent Shigella sonnei. The highest recovery of
bacterial isolates was obtained in pond water and the lowest
in tubewell water.
The results depicted that the combined effect of
physico-chemical properties of water on the growth and
propagation of bacteria in summer, rainy and winter seasons
were highly significant (P<0.01) in pond, river and sea
water, except in sea water in winter. The impact of physicochemical factors on the growth of bacteria in the tap and
tubewell water was very poor and insignificant (P>0.05).
Antibiotic resistant of bacterial pattern enteric
isolates obtained from water of domestic uses have revealed
that the maximum 90.15 per cent isolates weve resistant to
tetracycline, whereas the minimum 2.0 per cent isolates were
resistant to spectinomycin. Among these isolates E. coli.
possesed the highest and Shigella flexneri had the lowest
drug resistant property. Out of the total E. coli isolates,6.74 per cent were found to be resistant to all of the
antibiotics tested. Combination of antibiotics has been
found to be more efficacious on bacterial isolates. The use
of single antibiotic resulted in 83.95 to 112.67 per cent
resistant bacterial isolates, but when used in double,
triple or more combination, this resistance decreased even
up to zero level.
All of the strains, examined for the plasmid study,
exhibited resistance to tetracycline and frequently
possessed multiple antibiotic resistance properties. The
data obtained from the study revealed that the tetracycline
resistance property was encountered by four different river
isolates representing different genera. This could be due to
the presence of plasmid which appeared to confer resistance
to 20 mcg/ml streptomycin as well as tetracycline. The fifth
river isolate was found to be capable of transferring
tetracycline resistance and/or resistance to 100 mcg/m1
streptomycin by conjugation in broth mixtures in vitro.