The prevalence of bacterial resistance in clinical, food, water and some environmental samples in Southwest Nigeria

The resistance pattern and mechanisms of bacterial isolates obtained from clinical origin, soil, industrial effluent, orange juice products and drinking water were studied using commonly used antibiotics. The microbial load of the water samples, industrial effluent and orange juice products were 1.0 × 10¹–2.25 × 10⁶, 2.15 × 10⁵, and 3.5 × 10⁴–2.15 × 10⁵ cfu mL^–1, respectively. The faecal coliform test revealed that only two out of twenty orange juice products had MPN of 2 and 20, the MPN of water ranged from 1–1800, while the effluent had MPN of 1800. The bacterial isolates that were isolated include E. coli, S. aureus, P. vulgaris, S. marcescens, S. pyogenes, B. cereus, B. subtilis, Micrococcus sp., Klebsiella sp., P. aeruginosa, and Enterobacter sp. Also, clinical and soil isolates of P. aeruginosa were used in the study. Among the eight antibiotics tested for resistance on five strains of each bacterium, seven different resistance patterns were observed among the bacterial isolates obtained from water, effluent and orange juice products. Among the clinical and soil isolates of P. aeruginosa, four multiple-drug resistance patterns were obtained. Thirty strains of E. coli and S. aureus were tested for -lactamase production and fourteen strains, seven each of E. coli and S. aureus that had high Minimum Inhibitory Concentration values (MIC) for both Amoxycillin and Cloxacillin were positive.     

The occurrence of Shiga toxin-producing Escherichia coli in bathing water of the Sierra de la Ventana region, Buenos Aires Province, Argentina

The region of Sierra de la Ventana is located in the southwest of Buenos Aires Province, Argentina. Traditionally, this area has been devoted to livestock and agriculture, but tourism has had a significant development in recent years. In the region, there are many rivers and streams that are used for swimming and bathing. A survey of the occurrence of Shiga toxin-producing Escherichia coli (STEC) in these waters was conducted, and the microbiological quality of rivers and streams was investigated. No E. coli O157 was recovered by immunomagnetic separation. Nevertheless, the Shiga toxin gene, exclusively stx2 genotype, was detected in four non-O157 E. coli strains. Two STEC strains carried eae factor, but none of them harbored the EHEC-hlyA gene. Three of the STEC isolates belonged to samples obtained in the warm months, and one to the winter sampling. In the sample sites where STEC strains were isolated the counts of E. coli/100 ml exceeded or were close to the limit recommended by the United States Environmental Protection Agency for bathing water. The relationship observed between the rainy season and E. coli counts suggests that among the main causes for the hygienic indicator increase is the runoff of manure deposited on soils that may also induce the entrance of pathogens into the aquatic environment. This research, the first reporting STEC isolation from recreational waters in this area, revealed that streams and rivers from a beef-producing area of Argentina are a reservoir of STEC strains.     

Monitoring of multiple drug-resistant pathogens in a selected stretch of Bay of Bengal,India

The present work aims at identification of multiple drug-resistant pathogenic bacteria in a selected stretch, namely, Puri on the Bay of Bengal, India. Six stations at the coast of Puri were selected and samples of water and sediment were collected during the winter of 2008 and 2009 for this study. Thirty-eight pathogenic bacteria were isolated and identified from both the water and the sediment of 6 fixed stations (PU-1a, PU-1b, PU-2, PU-3, PU-4, and PU-5). The identified pathogens were Escherichia coli, Vibrio cholerae, Vibrio parahaemolyticus, Klebsiella pneumoniae, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Proteus mirabilis. Antibiotic sensitivity of the isolated bacteria was studied by using 12 selected antibiotics, commonly used for the medication of human beings and animals. The isolated pathogens from both the water and the sediment samples showed lowest resistance to chloramphenicol (C-30 μg) where as the pathogens showed highest level of resistance to ampicillin (10-μg) among the antibiotics used for the study. Among the isolated pathogens E. faecalis (PU-1a), P. aeruginosa (PU-2 and PU-3), E. coli (PU-3 and PU-4), and K. pneumonia (PU-4) showed resistance to more than four antibiotics. Out of the isolated species, 57.8% pathogens were multi-drug resistant. Antibiotic resistance indexes of all the stations were calculated and found to be in the range of 0.066 to 0.083.     

Isolation and Identification of Enterococci from Seawater Samples: Assessment of Their Resistance to Antibiotics and Heavy Metals

A hundred Enterococcus strains were isolated from seawater samples collected from coastal areas of Istanbul. Isolates were identified to the species level using standard biochemical tests specified by Facklam and Collins. The species distribution was as follows Enterococcus faecalis (96%), Enterococcus gallinarum (3%) and Enterococcus solitarius (1%). The resistance of bacteria to both heavy metals (zinc [Zn], iron [Fe], cadmium [Cd], chrome [Cr], cobalt [Co]) and antibiotics (ampicillin 10 μg [AP], penicillin G 10 Units [PG], gentamycin 10 μg [GM], streptomycin 10 μg [S], chloramphenicol 10 μg [C], erythromycin 15 μg [E], kanamycin 30 μg [K], amikacin 30 μg [AK], nalidixic acid 30 μg [NA], and vancomycin 30 μg [VA]) was evaluated. None of the strains was resistant to VA. It was found that among the 100 isolates, those that exhibit resistance to antibiotics, particularly NA, S and K, were also resistant all the heavy metals tested. To our knowledge this is the first report focusing on determination of resistance of environmental enterococci found in Istanbul against heavy metals and antibiotics. Thus, combined expressions of antibiotic and heavy metal resistance may help to reinforce ecological and epidemiological studies and to determine the role of these strains in antibiotic and heavy metal resistance dissemination.     

Faecal Coliform Bacteria in Febros River (Northwest Portugal): Temporal Variation, Correlation with Water Parameters, and Species Identification

Febros river water was sampled weekly, during 35 successive weeks, and analyzed for microbiological (total coliforms, faecal coliforms, faecal streptococci and enterococci) and chemical-physical (ammonia and temperature) parameters. All microbiological parameters were highly correlated with each other and with ammonia, suggesting that the simultaneous determination of all variables currently in use in the evaluation of the microbiological quality of waters is probably redundant, and could be simplified, and that ammonia should be tested as a sentinel parameter of the microbiological pollution load of Febros river. From the strains isolated from positive tubes of the faecal coliforms test (multiple tube fermentation technique) and retested in this assay, Escherichia coli, Klebsiella oxytoca and Klebsiella pneumoniae subsp. pneumoniae strains were positive, indicating that the faecal coliforms test is not totally specific for Escherichia coli, and can detect other bacteria. Considering that these Klebsiella spp. are not necessarily of faecal origin, it was concluded that the faecal coliforms test can overestimate true faecal pollution. From the strains isolated from positive tubes of the faecal coliforms procedure, only Escherichia coli strains were clearly positive in the β-D-glucuronidase test. All other species were negative or very weakly positive, suggesting that the assay of the β-D-glucuronidase activity is less prone to false positives than the faecal coliforms test in the quantification of Escherichia coli in environmental waters.     

Incidence of metal and antibiotic resistance in Pseudomonas spp. from the river water, agricultural soil irrigated with wastewater and groundwater

A total of 144 isolates of Pseudomonas spp. (48 each from the Yamuna River water, wastewater irrigated soil and groundwater irrigated soil) were tested for their resistance against certain heavy metals and antibiotics. Minimum inhibitory concentrations (MICs) of Hg^2?+?, Cd^2?+?, Cu^2?+?, Zn^2?+?, Ni^2?+?, Pb^2?+?, Cr^3?+? and Cr^6?+? for each isolate were also determined. A maximum MIC of 200 ??g/ml for mercury and 3,200 ??g/ml for other metals were observed. The incidences of metal resistance and MICs of metals for Pseudomonas isolates from the Yamuna water and wastewater irrigated soil were significantly different to those of groundwater irrigated soil. A high level of resistance against tetracycline and polymyxin B (81.2%) was observed in river water isolates. However, 87.5% of Pseudomonas isolates from soil irrigated with wastewater showed resistance to sulphadiazine, whereas 79.1% were resistant to both ampicillin and erythromycin. Isolates from soil irrigated with groundwater exhibited less resistance towards heavy metals and antibiotics as compared to those of river water and wastewater irrigated soil. Majority of the Pseudomonas isolates from water and soil exhibited resistance to multiple metals and antibiotics. Resistance was transferable to recipient Escherichia coli AB2200 strains by conjugation. Plasmids were cured with the curing agent ethidium bromide and acridine orange at sub-MIC concentration.     

Estimating the Microbial Risk of E. coli in Reclaimed Wastewater Irrigation on Paddy Field

Microbial risk was quantified to assess human health risk as a result of exposure to E. coli in reclaimed wastewater irrigation. Monitoring data on E. coli were collected from pond water in paddy rice plots during the growing season. Five treatments were used and each was triplicated to evaluate the changes in E. coli concentrations in experiments performed in 2003 and 2004. The Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion among farmers and neighboring children. A Monte Carlo simulation (10,000 trials) was conducted to estimate the risk associated with uncertainty. In this study, risk values ranged from 10⁻⁴ to 10⁻⁸. UV-disinfected irrigation water showed a lower risk value than others, and its level was within the range of the actual paddy rice field with surface water. Agricultural activity was thought to be safer after 1–2 days, when the paddy field was irrigated with reclaimed wastewater. Also, children were found to have a greater risk of infection with E. coli. This paper should be viewed as a first step in the application of quantitative microbial risk assessment of wastewater reuse in paddy rice culture.     

Assessment of pathogenic bacteria in water and sediment from a water reservoir under tropical conditions (Lake Ma Vallée), Kinshasa Democratic Republic of Congo

This study was conducted to assess potential human health risks presented by pathogenic bacteria in a protected multi-use lake-reservoir (Lake Ma Vallée) located in west of Kinshasa, Democratic Republic of Congo (DRC). Water and surface sediments from several points of the Lake were collected during summer. Microbial analysis was performed for Escherichia coli, Enterococcus (ENT), Pseudomonas species and heterotrophic plate counts. PCR amplification was performed for the confirmation of E. coli, ENT, Pseudomonas spp. and Pseudomonas aeruginosa isolated from samples. The results reveal low concentration of bacteria in water column of the lake, the bacterial quantification results observed in this study for the water column were below the recommended limits, according to WHO and the European Directive 2006/7/CE, for bathing water. However, high concentration of bacteria was observed in the sediment samples; the values of 2.65?×?10³, 6.35?×?10³, 3.27?×?10³ and 3.60?×?10⁸ CFU g^?1 of dry sediment for E. coli, ENT, Pseudomonas spp. and heterotrophic plate counts, respectively. The results of this study indicate that sediments of the Lake Ma Vallée can constitute a reservoir of pathogenic microorganisms which can persist in the lake. Possible resuspension of faecal indicator bacteria and pathogens would affect water quality and may increase health risks to the population during recreational activities. Our results indicate that the microbial sediment analysis provides complementary and important information for assessing sanitary quality of surface water under tropical conditions.     

Development of a PCR protocol for the detection of Escherichia coli O157:H7 and Salmonella spp. in surface water

Escherichia coli O157:H7 and Salmonella are pathogenic microorganisms that can cause severe gastrointestinal illness in humans. These pathogens may be transmitted in a variety of ways, including food and water. The presence of Salmonella and E. coli O157:H7 in surface waters constitutes a potential threat to human health when used for either drinking or recreation. As with most waterborne pathogens, Salmonella and E. coli O157:H7 are difficult to detect and enumerate with accuracy in surface waters due to methodological limitations. The aim of this study was to develop a protocol for the detection of Salmonella spp., E. coli O157:H7 and E. coli virulence genes (stx ₁, stx ₂ and eae) in water using a single enrichment step and PCR. In spiked water samples, PCR results showed high sensitivity (<3 CFU/L) for both microorganisms. The protocol developed in this study has been applied in different surface waters in association with microbiological and physical analysis. The frequency of PCR positive samples was 33% for Salmonella and 2% for E. coli O157:H7 producing intimin (eae) and Shiga-like toxin I (stx ₁). Moreover, the finding of amplicons corresponding to eae and stx ₁ genes in the absence of E. coli O157:H7 suggested the possible presence of other pathogenic bacteria that carry these genes (e.g. EHEC, Shigella strains). The results obtained showed that the developed protocol could be applied as a routine analysis of surface water for the evaluation of microbiological risks.     

Bacteria with dual resistance to elevated concentrations of heavy metals and antibiotics in Nigerian contaminated systems

Samples of soil, water, and sediments from industrial estates in Lagos were collected and analyzed for heavy metals and physicochemical composition. Bacteria that are resistant to elevated concentrations of metals (Cd^2?+?, Co^2?+?, Ni^2?+?, Cr^6?+?, and Hg^2?+?) were isolated from the samples, and they were further screened for antibiotic sensitivity. The minimum tolerance concentrations (MTCs) of the isolates with dual resistance to the metals were determined. The physicochemistry of all the samples indicated were heavily polluted. Twenty-two of the 270 bacterial strains isolated showed dual resistances to antibiotics and heavy metals. The MTCs of isolates to the metals were 14 mM for Cd^2?+?, 15 mM for Co^2?+? and Ni^2?+?, 17 mM for Cr^6?+?, and 10 mM for Hg^2?+?. Five strains (Pseudomonas aeruginosa, Actinomyces turicensis, Acinetobacter junni, Nocardia sp., and Micrococcus sp.) resisted all the 18 antibiotics tested. Whereas Rhodococcus sp. and Micrococcus sp. resisted 15 mM Ni^2?+?, P. aeruginosa resisted 10 mM Co^2?+?. To our knowledge, there has not been any report of bacterial strains resisting such high doses of metals coupled with wide range of antibiotics. Therefore, dual expressions of antibiotics and heavy-metal resistance make the isolates, potential seeds for decommissioning of sites polluted with industrial effluents rich in heavy metals, since the bacteria will be able to withstand in situ antibiosis that may prevail in such ecosystems.     

An Effective Means of Biofiltration of Heavy Metal Contaminated Water Bodies Using Aquatic Weed Eichhornia crassipes

Various aquatic plant species are known to accumulate heavy metals through the process of bioaccumulation. World’s most troublesome aquatic weed water hyacinth (Eichhornia crassipes) has been studied for its tendency to bio-accumulate and bio-magnify the heavy metal contaminants present in water bodies. The chemical investigation of plant parts has shown that it accumulates heavy metals like lead (Pb), chromium (Cr), zinc (Zn), manganese (Mn) and copper (Cu) to a large extent. Of all the heavy metals studied Pb, Zn and Mn tend to show greater affinity towards bioaccumulation. The higher concentration of metal in the aquatic weed signifies the biomagnification that lead to filtration of metallic ions from polluted water. The concept that E. crassipes can be used as a natural aquatic treatment system in the uptake of heavy metals is explored.     

Physicochemical and microbiological assessment of recreational and drinking waters

The present study was aimed to make an assessment of health risk due to pollution and human pathogenic bacteria associated with the recreational and drinking water sources in twin densely populated holy Indian cities Ayodhya and Faizabad. Though physicochemical studies revealed that the water available in the area is under recommended limits for human use, it is unsafe on account of poor microbiological quality of surface and ground water in the region. The most probable number (MPN) test results revealed the preponderance of ≥2,400 total coliforms (TC) (100 ml)^− 1 in river, pond, dug well and kund waters. Contrary to that, 94% tube wells, 32% hand pumps and 25% piped supply water were under safe limits having <3 TC (100 ml)^− 1. The shallow depth (~40 ft), water logging and presence of septic tanks in the near vicinity are the possible reasons of poor microbial quality of hand pump drinking water. The municipal supply water passes along sewage line where loose connections and/or cracks in pipe lead to mixing and contamination. The significant best quality of tube well water evident from the absence of TC could be attributed to the depth of well ≥150 ft and usually their location away from the habitation. A total of 263 bacteria from 186 water samples were isolated, and at least five genera of enteric bacteria from various water sources were identified morphologically and biochemically as Escherichia coli, Klebsiella sp., Enterobacter sp., Shigella sp. and Salmonella sp. The serotyping of 72 E. coli and 36 Salmonella sp. revealed 51 as E. coli O157 and 20 as Salmonella sp. The presence of enteric pathogens in water sources pose threat to human health and therefore call for immediate remedial measures.     

Restoration of fly ash dump through biological interventions

Field experiment on 10 ha area of fly ash dump was conducted to restore and revegetate it using biological interventions, which involves use of organic amendment, selection of suitable plant species along with specialized nitrogen fixing strains of biofertilizer. The results of the study indicated that amendment with farm yard manure at 50 t/ha improved the physical properties of fly ash such as maximum water holding capacity from 40.0 to 62.42% while porosity improved from 56.78 to 58.45%. The nitrogen content was increased by 4.5 times due to addition of nitrogen fixing strains of Bradyrhizobium and Azotobacter species, while phosphate content was increased by 10.0 times due to addition of VAM, which helps in phosphate immobilization. Due to biofertilizer inoculation different microbial groups such as Rhizobium, Azotobacter and VAM spores, which were practically absent in fly ash improved to 7.1 × 10⁷, 9.2 × 10⁷ CFU/g and 35 VAM spores/10 g of fly ash, respectively. Inoculation of biofertilizer and application of FYM helped in reducing the toxicity of heavy metals such as cadmium, copper, nickel and lead which were reduced by 25, 46, 48 and 47%, respectively, due to the increased organic matter content in the fly ash which complexes the heavy metals thereby decreasing the toxicity of metals. Amendment of fly ash with FYM and biofertilizer helped in profuse root development showing 15 times higher growth in Dendrocalamus strictus plant as compared to the control. Thus amendment and biofertilizer application provided better supportive material for anchorage and growth of the plant.     

Assessing environmental impacts of treated wastewater through monitoring of fecal indicator bacteria and salinity in irrigated soils

To assess the potential for treated wastewater irrigation to impact levels of fecal indicator bacteria (FIB) and salinity in irrigated soils, levels of Escherichia coli, Enterococcus, and environmental covariates were measured in a treated wastewater holding pond (irrigation source water), water leaving the irrigation system, and in irrigated soils over 2 years in a municipal parkland in Arizona. Higher E. coli levels were measured in the pond in winter (56 CFU 100 mL⁻¹) than in summer (17 CFU 100 mL⁻¹); however, in the irrigation system, levels of FIB decreased from summer (26 CFU 100 mL⁻¹) to winter (4 CFU 100 mL⁻¹), possibly related to low winter water use and corresponding death of residual bacteria within the system. For over 2 years, no increase in FIB was found in irrigated soils, though highest E. coli levels (700 CFU g⁻¹ soil) were measured in deeper (20–25 cm) soils during summer. Measurements of water inputs vs. potential evapotranspiration indicate that irrigation levels may have been sufficient to generate bacterial percolation to deeper soil layers during summer. No overall increase in soil salinity resulting from treated wastewater irrigation was detected, but distinct seasonal peaks as high as 4 ds m⁻¹ occurred during both summers. The peaks significantly declined in winter when surface ET abated and more favorable water balances could be maintained. Monitoring of seasonal shifts in irrigation water quality and/or factors correlated with increases and decreases in FIB will aid in identification of any public health or environmental risks that could arise from the use of treated wastewater for irrigation.     

Waterborne outbreaks in diarrhoea endemic foci of India: a longitudinal exploration and its implications

Diarrhoea remains a global public health enigma raising deep concerns for the health planners since contaminated potable water often spoils the community health structure. We hereby report a 6-year odd continuing outbreak surveillance report based on potable water indices, during which 264 water samples were screened from different districts of West Bengal, India. Samples were analysed for the presence of different enteropathogenic bacterial species by conventional molecular tools and their sensitivity to antibiotics. 78.03% samples were positive for enteropathogenic bacterial organisms and 75% samples harbored Coliform. 45.45, 12.12, and 4.16% samples were positive for E.coli, V. cholerae, and V. mimicus, respectively. Diarrhoeagenic E.coli 7 EPEC, 10 ETEC, and 2 EIEC were isolated along with 2 V. cholerae O1 Ogawa (ctxA and tcpA ElTor positive), one each from tube well and pond. Interestingly, 4 V.cholerae non-O1/non-O139 also harbored hlyA gene. The detection of toxin genes among this bacterial pool of sampled water indicates the fallout of the potable water sources, thus enabling us to establish that it is none other than the contaminated potable water system which often wreaks havoc in the south Bengal diarrhoeal menace. The consequences are further complicated by the presence of drug-resistant pathogenic bacterial pool to fluoroquinolone, beta-lactams, and cephalosporins, in the accessible potable water, with threats of outbreaks exploding into an epidemic, given suitable environment, poor sanitation, and unhygienic practices. Therefore, we strongly recommend re-modelling of ‘point-of-use water disinfection’ measures and adequate personal hygiene for healthier community life.     

Monitoring E. coli and total coliforms in natural spring water as related to recreational mountain areas

Natural spring water has unique properties, as it is rich in minerals that are considered to be beneficial to human health. A survey of the microbiological quality of natural spring water was conducted to assess possible risks from the consumption of the water by visitors in recreational mountain areas located in Seoul, South Korea. The densities of total coliforms and Escherichia coli were measured during the spring and the summer of 2002 to investigate the presence of coliform bacteria in the drinking spring waters. Total coliforms were detected in all samples and the mean density of total coliforms was up to a maximum of 228 CFU/mL. Detectable E. coli was found in 78% of all samples and the mean densities of E. coli varied from a minimum of 0 CFU/mL to a maximum of 15 CFU/mL in all samples. Malfunctioning septic systems and wildlife population appear to be the main source of E. coli contamination. Presence of E. coli in natural spring water indicates potential adverse health effects for individuals or populations exposed to this water. The fecal contaminated spring water may present an unacceptable risk to humans if it is used as raw drinking water.     

Comparative study of fluorogenic and chromogenic media for specific detection of environmental isolates of thermotolerant Escherichia coli

In a field study 78 water samples were analysed employingFluorocult Brilla Broth (BB) and its performance was comparedwith standard MPN procedure. Out of 78 water samples analysed 56(71.7%) samples yielded positive reactions in BB whereas, 50(64.1%) samples were positive by standard fecal coliform test.A comparative study of fluorogenic and chromogenic mediacontaining substrate -D glucuronide for specificdetection of environmental isolates of 313 thermotolerant E.coli has been undertaken. Five fluorogenic media wereused: Fluorocult MacConkey agar (MCA), Fluorocult ECD agar(ECD), Fluorocult VRB agar (VRB), Fluorocult E. coli0157:H7 agar (ECH7) and Fluorocult Brilla Broth (BB) andChromogenic Chromocult agar (CCA). BB and CCA were found to behighly specific and sensitive media to detect E. coli asall E. coli yielded positive reaction on them. On ECH7 andECD agar 67.5 and 64.9 of E. coli isolates gave positivereaction, respectively. Low sensitivity was observed in case ofMCA and VRB agar in detecting E. coli. The performance ofBB appears to be better when compared with standard MPNprocedure employing MacConkey broth/Brilliant green bile brothin detecting E. coli in drinking water.     

Characterization and statistical modeling of bacterial (Escherichia coli) outflows from watersheds that discharge into southern Lake Michigan

Two watersheds in northwestern Indiana were selected for detailed monitoring of bacterially contaminated discharges (Escherichia coli) into Lake Michigan. A large watershed that drains an urbanized area with treatment plants that release raw sewage during storms discharges into Lake Michigan at the outlet of Burns Ditch. A small watershed drains part of the Great Marsh, a wetland complex that has been disrupted by ditching and limited residential development, at the outlet of Derby Ditch. Monitoring at the outlet of Burns Ditch in 1999 and 2000 indicated that E. coli concentrations vary over two orders of magnitude during storms. During one storm, sewage overflows caused concentrations to increase to more than 10,000 cfu/100 mL for several hours. Monitoring at Derby Ditch from 1997 to 2000 also indicated that E. coli concentrations increase during storms with the highest concentrations generally occurring during rising streamflow. Multiple regression analysis indicated that 60% of the variability in measured outflows of E. coli from Derby Ditch (n = 88) could be accounted for by a model that utilizes continuously measured rainfall, stream discharge, soil temperature and depth to water table in the Great Marsh. A similar analysis indicated that 90% of the variability in measured E. coli concentrations at the outlet of Burns Ditch (n = 43) during storms could be accounted for by a combination of continuously measured water-quality variables including nitrate and ammonium. These models, which utilize data that can be collected on a real-time basis, could form part of an Early Warning System for predicting beach closures.     

Comparison of ALAD activities of Citrobacter and Pseudomonas strains and their usage as biomarker for Pb contamination

Delta-aminolevulinate dehydratase (ALAD) activity has been used in prokaryotes and eukaryotes as a biomarker for environmental lead (Pb) exposure and toxicity. Microorganisms are sensitive indicators of toxicity at the fundamental level of ecological organization, but bacterial biomarker studies are focused on the Pseudomonas strains in Group I and E coli. The objectives of the present work were to determine if Burkholderia gladioli belonging to group II, due to its 16SrRNA similarity, can be used as biomarker in metal contamination and compare its possible usage with Pseudomonas aeruginosa and Citrobacter freundii (previously known as Esherichia freundii) and Bacterium freundii which are classified in Group I. In this study, ALAD activity in an environmental strains of Burkholderia gladioli, Pseudomonas aeruginosa, Citrobacter freundii were investigated to evaluate potential inhibition by Pb and other toxic metals. When the ALAD activity of Burkholderia gladioli was tested, Co and Pb decreased activity by 27 and 71%, respectively. In addition to these findings, Zn increased the activity up to 26%. These effects were found to be statistically meaningful (p < 0.05). It was determined that the increase of lead concentration inhibites the ALAD activity at each of the three strains. There was a statistically significant dose–response relationship between ALAD activity in cells of Burkholderia gladioli and Pb (Pearson correlation coefficent = −0.665; r ² = 0.665, and p < 0.001). The strongest ALAD inhibition which was measured was 90% at Burkholderia gladioli when protein extracts were incubated with 750 μM of Pb. The relationship between Pb and ALAD activity was statistically described by [ALAD Activity] = 0.476−0.000597 × [Pb]. According to the obtained results, we suggest that the ALAD of Burkholderia gladioli can be used as a biomarker for lead contamination in the environment.     

Quantitative Analyses of Pollution-Indicator and Pathogenic Bacteria in Mumbai Waters from Ballast Water Exchange Perspective

As large numbers of ships either take in ballast from or discharge their ballast into the Mumbai Harbor region, it is pertinent to quantify microorganisms of health concerns and suggest on the suitability of water for ballasting purposes. To meet with this main aim, a selected set of general and pathogenic bacterial groups and their seasonal variations were studied from the Mumbai Harbor area. Sampling was carried out during postmonsoon (November 2001), pre-monsoon (April 2002) and monsoon (October 2002) periods. We quantified total coliforms and eight other groups of known human pathogenic bacteria from water, sediment, marine plant and animal samples collected in and around Mumbai Harbor. When compared with similar studies from other parts/harbors of the world, the Mumbai Harbor area has over 100-times higher levels of coliforms. The serotypes of Escherichia coli O157 and Shigella-Alkaligens Dispar group were abundant throughout the year. Even Vibrio cholerae, V. parahaemolyticus, Salmonella spp., campylobacters and aeromonads were present in large numbers. This comprehensive study, conducted with a view to quantify these bacterial groups and to evaluate the suitability of these waters for ballasting purposes, clearly suggests that both ballasting and deballasting be avoided in this region and alternative procedures should be developed for treating/handling ballast water.