Bacteriological assessment of Spoon River water quality

A Study on the Microbiological Status of Mineral Drinking Water

INTRODUCTION

Water-borne diseases constitute a major health burden in Bangladesh. The objective of this study was to assess the overall quality of mineral water samples that obtained from different shops of Dhaka city.

MATERIAL AND METHODS

To achieve the above-mentioned objective, methods of heterotrophic plate count (HPC) and total coliform count (TCC) were applied. Moreover, isolated colony from mineral water samples were characterized by using biochemical and antimicrobial susceptibility tests.

RESULTS

Different water samples showed different HPC ranged from 1.0×10 to 8.00×102. Antimicrobial sensitivity test of some selected bacteria viz S. intermedius, S. aureus, S. felis and S. Saccharolyticus were performed. It was observed that Staphylococcus spp. isolates were susceptible to erythromycin, tetracycline, norfloxacin and ciprofloxacin. Furthermore, a few Staphylococcus spp. isolates were intermediate resistant to penicillin and oxacillin. However, most of the Staphylococcus spp. isolates were resistant to cefixime.

CONCLUSION

The results indicate that mineral water serves as a reservoir of various bacteria and that people in Dhaka city, who are the consumers of these water, might get diseases. This study emphasizes the need for elaborated microbiological examinations of mineral drinking water commonly used in Dhaka city.

A study on the existence of Vibrio cholerae non-O1 in the river

OBJECTIVE

The aim of the present study is Vibrio cholerae non-O1 existing in river. Bacteria are known to inhabit all kinds of environment. Vibrionaceae is widely distributed in environmental water. Vibrio spp. have been identified as a cause of toxicity in fish and shellfish. One condition affecting the survival of pathogenic microorganisms in environmental water is the salt concentration, and they have been reported to inhabit brackish water. However, V. cholerae non-O1 has also been detected in fresh water, and its properties suggest that it can survive in river water.

METHODS

Sampling was performed 4 times at 4 points during a 5-month period from July to November at about 1-month intervals from the Sagami River in 1985. River water bacteria were identified, and V. cholera non-O1 isolated. I investigated the relationship between the bacterial flora in river water and the detection of V. cholerae non-O1.

RESULTS

There were significant differences in the composition of bacterial flora with and without the isolation of V. cholerae non-O1 (Chi-square test) (χ(2) = 24.70 > 22.0 (p = 0.005), df = 8). A correlation between changes in the composition of the river water bacterial flora and detection of V. cholerae non-O1 was identified.

CONCLUSION

Therefore, V. cholerae non-O1 exists in the river.

Fecal indicator bacteria persistence under natural conditions in an ice-covered river

Total coliform (TC), fecal coliform (FC), and fecal streptococcus (FS) survival characteristics, under natural conditions at 0 degrees C in an ice-covered river, were examined during February and March 1975. The membrane filter (MF) technique was used throughout the study, and the multiple-tube (MPN) method was used in parallel on three preselected days for comparative recovery of these bacteria. Survival was studied at seven sample stations downstream from all domestic pollution sources in a 317-km reach of the river having 7.1 days mean flow time (range of 6.0 to 9.1 days). The mean indicator bacteria densities decreased continuously at successive stations in this reach and, after adjustment for dilution, the most rapid die-off was found to occur during the first 1.9 days, followed by a slower decrease. After 7.1 days, the relative survival was TC less than FC less than FS, with 8.4%, 15.7%, and 32.8% of the initial populations remaining viable, respectively. These rates are higher than previously reported and suggest that the highest survival rates for these bacteria in receiving streams can be expected at 0 degree C under ice cover. Additionally, the FC-FS ratio was greater than 5 at all stations, indicating that this ratio may be useable for determining the source of fecal pollution in receiving streams for greater than 7 days flow time at low water temperatures. The MPN and MF methods gave comparable results for the TC and FS at all seven sample stations, with both the direct and verified MF counts within the 95% confidence limits of the respective MPNs in most samples, but generally lower than the MPN index. Although FC recovery on membrane filters was comparable results at stations near the pollution source. However, the results became more comparable with increasing flow time. The results of this study indicate that heat shock is a major factor in suppression of the FC counts on the membrane filters at 44.5 degree C. Heat shock may be minimized by extended incubation at 35 degrees C before exposure to the higher temperature.

Bacteriological quality assessment of fresh marketed lettuce and fennel

One-hundred and twenty samples of lettuce and 89 samples of fennel purchased from five retail outlets in the city of Bari (Italy) from October 1973 through September 1975 were examined for viable aerobic bacteria (AB), total coliforms (TC), fecal coliforms (FC), fecal streptococci (FS), and salmonellae. Comparative tests indicated that the results of bacteriological analysis of wash water from either vegetable by a membrane filter technique compared favorably with those of conventional cultural examination of the vegetable tissue for the purpose of providing an indication of the bacteriological quality of the samples. Using the membrane filter technique, 2-year average counts of 6.59 X 10(7) for AB, 5.95 X 10(4) for TC, 6.13 X 10(3) for FC and 2.24 X 10(3) for FS/100 g (fresh weight) were obtained with lettuce; with fennel, the corresponding figures were 2.32 X 10(6) for AB, 7.82 X 10(4) for TC, 7.8 X 10(4) for FC, and 3.15 X 10(3) for FS. Indicator bacteria were present in all samples examined. In addition, 68.3% of the lettuce and 71.9% of the fennel samples yielded one or more of the following Salmonella serotypes: S. schottmuelleri, S. typhimurium, S. thompson, S. dublin, S. typhi, and S. anatum.