Potentially pathogenic bacteria isolated from different tropical waters in Sri Lanka

Availability as well as access to drinking water is one of the considerable constraints for achieving sustainable goals in many countries while microbial contamination has exacerbated this issue more significantly. The increasing trend of population and industrialization for economic growth has adversely been affecting fresh water resources that eventually leading to scarcity of available drinking water. Hence, controlling water pollution along with focusing on alternative water sources are important for ensuring access to safe drinking water. This study aimed to determine the biological water quality parameters of rainfall water in the water-scarce areas of Bangladesh. About sixty rainwater samples collected from seven different districts were collected for microbial analysis in particular Total Coliform (TC) and Fecal Coliform (FC) by using membrane filtration and direct counting method. The result found that 70 % of samples were free from total coliform, whereas only 5 % samples showed above 100 colonies. On the other hand, 83% samples were free from fecal coliform, whereas only 2% samples were within the range of 11-100 colonies. This study has also revealed that most of the samples collected from Rangamati and Khulna district were free from total coliform and fecal coliform. This study may also encourage people living in these water scarce areas to come forward for rainwater harvesting system as a prospective tool for achieving sustainable goal in drinking sector of Bangladesh.
 Stamford Journal of Microbiology, Vol.8(1) 2018: 24-26

Many communities in Kumasi, Ghana, are increasingly dependent on boreholes and hand dug wells. The aim of this study was to examine the drinking water suitability of 6 wells and 3 boreholes in peri-urban communities in Kumasi, between December 2003 and January 2005. Total coliforms, faecal coliforms and enterococci were enumerated using the standard most probable number method and membrane filtration methods. The heavy metals in the water samples were determined using the atomic absorption spectrometry method. Overall, significantly higher bacterial counts were recorded during the wet (rainy) season compared to the dry (harmattan) season. Faecal coliforms counts (FCC) in 3 borehole samples ranged between 3 x 101 and 3.5 x 107 per 100 ml (geometric means 1.82, 1.75 and 2.8 x 104) while mean numbers of enterococci were 103-105 times lower. The range and geometric means of FCC was similar in samples from wells but levels of enterococci were 8 times higher than in boreholes. Manganese and iron levels were well within the WHO standards for all 9 sites but lead levels except for one site (Boadi) were all higher than the WHO standard. A brief sanitation survey at each site suggested that wells and boreholes were frequently cited near latrines, refuse tips and other social amenities, and in the vicinity of domestic or grazing animals. In Kumasi, the water from shallow wells and boreholes, upon which the local communities depend is of poor quality. The data are being used to advise the local government. An integrated approach is required to minimise faecal pollution of wells and boreholes within peri-urban communities. Key words: Boreholes, enterococci, faecal coliforms, peri-urban communities, total coliforms, wells.

The quality of drinking water at the point of delivery to the consumer is crucial in safeguarding consumer’s health. The current study was undertaken to assess the changes in residual chlorine content with distance in water distribution system in Gwalior city of Madhya Pradesh and assess its relation with the occurrence of total and faecal coliforms. Water samples were collected from the exit point of the treatment plant and taps at consumer households at an interval of 1 to 2 km. A total of 56 water samples were tested to determine residual chlorine content and presence of total and fecal coliforms using standard methods. Average concentrations of residual chlorine from all sampling location were between 0.08 to 0.98 mg/L. Total coliform was found at most of the sampling locations in the range of 0.82 to 7.15 MPN/100 ml. The fecal coliform at all sampling locations was found in the range of 0 to 4.10 MPN/100 ml. With time, the residual chlorine in the transported water dechlorinates. After covering some distance, the residual chlorine of the water was completely diminished thereby supporting massive microbial growth. The study proposed the likely causes of the transit dechlorination of water and recommended carrying out compulsory chlorination at water sources while maintaining reasonable residuals at the consumers’ end to eliminate the bacteriological contamination. Key words: Residual chlorine, total and fecal coliforms, drinking water chlorination, water contamination.

Bacteriological analyses of 3,942 water samples was undertaken. Samples hailed from many different sources, or rather, reservoirs (1,033), faucets (1,594), swimming pools (789), spring water (96), private wells (350) and others (80). They were obtained for routine testing between 1996 and 1999 and comparatively analyzed for total and fecal coliform bacteria by a multiple-tube fermentation technique. Total and fecal coliform bacteria were detected in 595 and 235 of the water samples, respectively, and were associated with the following factors: as raw water, chlorinated water, source water, wet season, dry season, pH, and disinfectant residuals. As expected, the highest number of water samples contaminated by total (362) and fecal (159) coliform bacteria was found in the raw water at source and at the consumption end among urban and rural communities. The people of these areas use water directly from available sources, without any treatment and are therefore exposed to a variety of water-related diseases.

Agricultural waters may be a source of produce contamination in the fields. The purpose of this study was to determine microbiological quality of agricultural surface water sources in Muş plain. Water samples were examined for four different agricultural surface water resources including two ponds and two streams during the agricultural season. The population of total coliform and fecal coliform were enumerated with Most Probable Number in 100 mL water samples (MPN 100 mL). Generic Escherichia coli populations were determined as MPN and CFU isolates in 100 mL water samples. Generic E. coli isolates were recovered for antibiotic susceptibility test and genetic relationships analyses with RAPD PCR. The presence of Salmonella was also determined in 100 mL water samples with confirmation of InvA gene presence after isolation of presumptive colonies. Total coliform population reached >2.96 log MPN 100 mL-1. The E. coli population in all surface water sources ranged from 0 to >2.96 log MPN 100 mL-1 and 0 to 2.78 log CFU 100 mL-1. The presence of Salmonella was found to be positive in a total of three water samples in two sources (5%). E. coli isolates were found to be resistant to rifampicin (100%), erythromycin (100%), and vancomycin (97.05%). Generic E. coli populations isolated from streams were not grouped together in similar clusters. Results of this study indicate that agricultural surface water sources in Muş Plain may contain could be a contamination source when in contact with the produce.

A survey of the microbiological quality of water from 194 boreholes (97 privately owned and 97 communal boreholes) in the rural Thitale-Hlanganani area of the Limpopo Province, South Africa was carried out between August 2002 and August 2003. Very little information on the microbiological quality of privately-owned boreholes in rural communities is available raising concerns about the safety of these groundwater supplies. In this study, levels of total coliforms, thermotolerant (faecal) coliforms, faecal enterococci, Clostridium perfringens (vegetative cells and spores) and somatic coliphages were determined for community and privately-owned borehole water. The average counts for total coliforms, faecal coliforms, faecal enterococci and Clostridium perfringens exceeded the South African recommended guideline limits of 0-10 counts.100 ml(-1) for total coliforms and 0 counts. 100 ml(-1) for faecal coliforms, faecal enterococci and Clostridium perfringens respectively. Comparisons between the levels of indicator bacteria present in private and communal boreholes during dry seasons indicated a statistical difference for faecal enterococci bacteria (p = 0.005) and Clostridium perfringens (p = 0.08). Comparisons between the levels of indicator bacteria present in private and communal boreholes during rainy seasons indicated statistical differences between total coliforms (p = 0.05), faecal coliforms (p = 0.03) and Clostridium perfringens (p = 0.009) bacteria. No significant differences in the presence of somatic coliphages in both private and communal borehole water were see. The results indicated the need for environmental impact assessment studies to monitor the microbiological quality of groundwater sources in rural communities.

The relationships between indicator bacteria and the organic load were conducted over a year in Lake Pamvotis, in northwest Greece. Total coliforms (TC) and fecal coliforms (FC) were found in water samples from five different sampling stations. Organic load was estimated using biological oxygen demand (BOD) and chemical oxygen demand (COD) parameters. Increased TC and FC levels were found close to heavily polluted areas. Near-bottom samples had higher levels of bacteria and the numbers of TC and FC were increased during rainfall periods. Low or negative correlations were also observed between the bacteriological indices and BOD and COD levels, thus strengthening the hypothesis that indicator bacteria mainly depend upon the origin of pollution rather than the amount of the organic load. It is conceivable that systematic bacteriological and chemical indices must be monitored in order to evaluate the ecosystem and to protect public health.

Movement of faecal indicator organisms in earthworm channels under a loamy arable and grassland soil

Monitoring microbial safety and evaluation of removal efficiency from drinking water in Ahvaz, Iran

<div class="htmlview paragraph">Ozone and ultraviolet (UV) light have been shown to be effective in treating emerging pathogens that are not affected by the current standard treatment of chlorine. The hypothesis of this study was that a combined treatment of UV light and ozone would result in greater pathogen reduction than a large dose of either one individually. In the one-way studies for ozone and UV light, the ozone treatments took at least twice as long as the UV treatments to achieve the same extent of reduction in the microbial population. Specifically, 60 min for ozone and 30 min for UV light for a 4-log reduction in Heterotrophic plate counts (HPC's); 10 min for ozone and 3 min for UV light for a 3-log reduction in total coliforms and fecal coliforms; and, 6 min for ozone and 3 min for UV light for a 2-log reduction in coliphage. The ozone treatments, however, unlike the UV treatments, resulted in no positive re-growth in bacteria after treatment. Ozone and UV light acting simultaneously exhibited not merely additive, but synergistic effects, in reducing the microbial populations, with the exception of when low levels (2 min UV and 1 min ozone) of both factors were used. Specifically, the following treatment combinations yielded the maximum microbial reductions: low level of UV (1 min) and high level of ozone (4 min) for HPC's; high level of UV (2 min) and high level of ozone (4 min) for total Coliforms and fecal coliforms; and either one of the foregoing treatments for the overall microbial population. The synergistic effects between UV light and ozone allowed for lower UV and ozone levels to achieve the same extent of microbial reduction achieved by either factor acting separately. Thus, 2 min of ozone and 2 min of UV light applied simultaneously was just as effective as 6-8 min of ozone only or 2.5 min of UV light only. This synergistic effect should lead to reduced energy consumption while maintaining the level of disinfection required. If UV light and ozone were to be applied successively, the most effective sequence of application would be ozone first followed by UV light.</div>

El presente trabajo analiza la eficacia del tratamiento de agua procedentes del río Rímac. Se comparan muestras de agua no tratadas con las fases sucesivas del tratamiento: decantación, filtración y clorinación. La cuantificación de colifagos fue realizada por los métodos de Capa Simple y Filtro de Membrana. Los Coliformes Totales (CT), Coliformes Termotolerantes (CTT) y Bacterias Heterótrofas (BH) fueron determinados por los métodos del Número Más Probable (NMP) y Filtro de Membrana. La cepa estándar de E. coli C ATCC 13706 fue utilizada como hospedera de colifagos. Los promedios de colifagos cuantificados fueron de 2267,25 UFP/100 mL en las muestras sin tratamiento; 2,11; 2,04 y 1,07 UFP/100 mL en las muestras procedentes de la decantación, filtración y clorinación respectivamente. No se detectaron CT y CTT en muestras de agua clorinada. La correlación entre colifagos y CT en muestras de agua decantada y filtrada (r = 0,3793 y r = 0,3629 respectivamente) fueron significativas (p<0,05). En las muestras de agua sin tratamiento no fueron significativas las correlaciones (r = 0,3048, p>0,05). La correlación entre colifagos y los CTT con las muestras de tratamientos fue significativa (r = 0,7129; 0,5326 y 0,4612, para muestras con decantación, filtración y clorinación respectivamente, p<0,05). Los porcentajes de remoción microbiana respecto de la muestras de agua sin tratamiento fueron del 99,95 % para los colifagos, 99,99 % para las BH y >99,99 % para los CT y CTT.

To describe the extent of faecal pollution and point of use water treatment strategy during and after the 2004 flood in Dhaka. A total of 300 water samples were collected from 20 different drinking water sources in Kamalapur, Dhaka city from August 2004 to January 2005. The level of faecal contamination was estimated using measurements of faecal indicator bacteria (total coliforms, faecal coliforms and faecal streptococci) and isolation of Vibrio cholerae was carried out following standard procedures. Total dissolved solids, dissolved oxygen, hardness, chloride and pH were also monitored. The efficacy of four disinfectants including Halotab, Zeoline-200, alum potash and bleaching powder were tested as point of use water treatment agents. The unacceptable level of contamination of total coliforms (TC), faecal coliforms (FC) and faecal streptococci (FS) ranged from 23.8% to 95.2%, 28.6% to 95.2% and 33.3% to 90.0%, respectively. The isolation rates of V. cholerae O1 and O139 were both 0.33%, and non-O1/non-O139 was 7.0%. Water collected during and after floods was contaminated with TC, FC, FS and V. cholerae. Although alum potash, bleaching powder, Halotab and Zeoline-200 were all effective general disinfectants, Halotab and Zeoline-200 were superior to bleaching powder and alum potash against FC. During and after floods, point of use water treatment could reduce waterborne diseases among flood-affected people.

Treated effluent discharge can significantly alter river water quality by affecting parameters such as pH, turbidity, conductivity, and coliform levels, thereby posing risks to both ecosystems and human health. This study evaluated the impact of effluent discharge from the Wupa Wastewater Treatment Plant Abuja, Nigeria on the water quality of the Wupa River. A refined parametric water quality index was developed to enhance monitoring precision, as traditional indices often lack sensitivity to variations in individual parameters. Water samples were collected during the rainy season’s peak mixing period (June–August) from six stations: the influent (INF), effluent (EFF), the point of discharge (POD), upstream of POD (UPOD), and two downstream locations (1kmPOD and 2kmPOD). The samples were analyzed for physical appearance, pH, temperature, conductivity, turbidity, total coliforms, and fecal coliforms. The parametric index incorporated three components: concentration factor, percentage equivalence, and percentage change, to capture parameter-specific changes. Results revealed distinct spatial variations in water quality across the stations. The INF had poor quality, with turbidity between 203–209NTU, total coliforms up to 6000/100 mL, and fecal coliforms also reaching 6000/100 mL, along with a darkish appearance. The EFF showed improvement, with turbidity reduced to 16–19NTU and total coliforms to 400–2000/100 mL, indicating partial treatment success. The UPOD station showed moderate pollution, with turbidity between 69–94 NTU, total coliforms at 600–3000/100 mL, and fecal coliforms ranging from 880–1600/100 mL. At the POD, contamination intensified: turbidity rose to 84–95 NTU, total coliforms increased to 1750–4500/100 mL, and fecal coliforms to 400–900/100 mL. Further downstream, values remained high—turbidity (80–85 NTU), total coliforms (650–3000/100 mL), and fecal coliforms (700–1220/100 mL). pH remained nearly neutral (6.91–7.65), and temperature ranged from 23.8–28.3 °C. Statistical analysis (ANOVA and t-tests) showed significant differences (p < 0.05) in conductivity (245–345 µS/cm), turbidity, and all coliform counts across stations, while differences in pH and temperature were not significant. The parametric index further revealed that treated effluent influenced river quality through elevated turbidity, minor pH variations (+2% in June, −2% to −4% in July and August), and significant increases in coliform levels. Temperature at the POD rose by 5%–12% but declined downstream. Conductivity increased at the POD(+15.5% to +23%) and remained elevated downstream. Turbidity also increased at the POD(+21.7% in June) before declining. Total coliforms surged at the POD(+50% to +191.7%), with residual contamination downstream, while fecal coliforms showed mixed patterns. These findings indicate that although some parameters return to near-background levels within 1 km, microbial contamination persists, raising concerns about waterborne diseases and the safety of downstream water use. The study concludes that the parametric water quality index is effective in assessing site-specific impacts of effluent discharge and underscores the urgent need for improved wastewater treatment and ongoing water quality monitoring to protect public health and environmental integrity.

Surface water quality in Dolisie (southwest of the Republic of Congo) is strongly impacted by human activities, particularly domestic wastewater discharge, agriculture, and livestock farming, leading to progressive degradation of water resources and posing risks to public health as well as domestic and agricultural uses. This study assessed water quality through analysis of physico-chemical and bacteriological parameters at several sites representative of domestic and agricultural areas. Physico-chemical analysis showed that pH ranged from 5.5 (Ninja Lake) to 9.9 (marsh near the Orthodox Church), with a mean of 6.58 ± 1.18. Water temperature varied from 25.36°C (upstream of the Loubomo River) to 28.5°C (Tahiti fish ponds), with an average of 26.83 ± 0.93°C. Electrical conductivity ranged from 115.66 to 315.33 µS/cm (mean 213.65 ± 73.18 µS/cm), while total dissolved solids (TDS) varied from 57 to 210.5 ppm (mean 112.52 ± 46.70 ppm). Three heavy metals were detected: cadmium (0.049–0.070 ppm, mean 0.057 ± 0.005 ppm), copper (0.0217–0.0509 ppm, mean 0.037 ± 0.010 ppm), and zinc (0.0004–0.00311 ppm, mean 0.004 ± 0.008 ppm). Microbiologically, total mesophilic aerobic flora (TMAF) ranged from 1,000 to 6,000 CFU/100mL (mean 3,333 ± 1,670), total coliforms from 69 to 193 CFU/100mL (mean 133 ± 43), and fecal coliforms from 32 to 102 CFU/100mL (mean 64 ± 21), exceeding WHO standards and indicating significant fecal contamination. Fecal streptococci ranged from 30 to 72 CFU/100mL, &amp;lt;i&amp;gt;Staphylococcus&amp;lt;/i&amp;gt; spp. from 14 to 97 CFU/100mL, &amp;lt;i&amp;gt;Salmonella&amp;lt;/i&amp;gt; from 40 to 110 CFU/100mL, &amp;lt;i&amp;gt;Shigella&amp;lt;/i&amp;gt; from 19 to 77 CFU/100mL, and &amp;lt;i&amp;gt;Pseudomonas &amp;lt;/i&amp;gt;&amp;lt;i&amp;gt;aeruginosa&amp;lt;/i&amp;gt; from 15 to 62 CFU/100mL. Correlation analyses revealed significant relationships: temperature correlated with total coliforms (r = 0.69) and fecal coliforms (r = 0.63), electrical conductivity correlated with TDS (r = 0.91), and several bacterial groups showed positive correlations among themselves. Principal component analysis associated the F1 axis (42.24% of variance) with microbiological parameters and the F2 axis (20.7%) with physico-chemical parameters. These findings reveal progressive deterioration of surface water quality in Dolisie and emphasize the urgent need for sustainable management measures, public awareness, and wastewater control to preserve water resources and protect public health.

A collaborative study was conducted in 18 laboratories to assess the performance of the hydrophobic grid membrane filter method against that of the AOAC official first action method 46.013-46.016 for enumerating total and fecal coliforms and Escherichia coli. The study was carried out on frozen breaded fish, raw comminuted poultry, unroasted walnut pieces, ground black pepper, and cheddar cheese. The hydrophobic grid membrane filter method recovered significantly larger numbers of target bacteria in 7 of the food/analysis combinations: fecal coliforms in fish; E. coli in poultry; fecal coliforms and E. coli in walnuts; and total coliforms, fecal coliforms and E. coli in black pepper. Random error (Sr2) associated with the hydrophobic grid membrane filter method was significantly lower than that of the reference method in over 30% of the paired sample series. The hydrophobic grid membrane filter method for total coliform, fecal coliform, and E. coli enumeration in foods has been adopted official first action.