Krishnan Muthukumar

Antibiotic resistant pathogens versus human impacts: A study from three eco-regions of the Chennai coast, southern India

We assessed the occurrence of pollution indicators and antibiotic resistant bacterial isolates from water and sediment samples of three different eco-regions of the Chennai coast between March - May of 2010. Total of 960 bacterial strains belonging to four genera were isolated which show the highest frequencies of resistance to vancomycin (53.6%) and penicillin (52.6%) (except Enterococcus sp., which is highly resistant to erythromycin) and lowest frequencies of resistance to chloramphenicol (3.43%), ciprofloxacin (3.95%), gentamicin (4.68%), and tetracycline (6.97%). The E. coli, Vibrio sp., Salmonella sp. and Enterococcus sp. show high frequency of resistance to 2-5 antibacterials of 60.4%, 45.83%, 69.16% and 46.6%, respectively. High pollution indices (PI - 6.66-14.06) and antibiotic resistance indices (ARI - 0.29-0.343) indicate that the coastal environment is highly exposed to antibiotic sources that suggesting to avoid direct contact.

Microbial Pollution Indicators in the Cauvery River, Southern India

The River Cauvery is one of the largest rivers of the Indian subcontinent. It originates from the Brahmagiri range of the Western Ghats, and flows for about 800 km west to east before debauching at the Bay of Bengal. Because of its importance in the Indian culture and dense population residing at its banks, it faces several forced and unforced human activities. This river system of Tamilnadu was studied in detail for the present status of water quality. Water samples were collected from 17 different sites from the Krishnarajasager reservoir up to the estuarine regions. Microbiological analysis was performed during four seasons (2010). Measured parameters include, bacterial analysis; total viable count (TVC), total coliform count (TC), total streptococci count (TS) and six different types of pathogenic bacteria. It is inferred from the study that the total coliforms (TC) were in the magnitude of 103 ml−1 for most of the sites, - higher than the permissible limits. The pollution indices (PI) ratio were high in all the seasons and maximum was observed in urban (S6 – 12.5) areas. The monsoon season showed the presence of higher levels of bacterial pollution than other seasons.

Synthesis of silver nanoparticles using bacterial exopolysaccharide and its application for degradation of azo-dyes

Highlights • The green synthesis of AgNPs using bacterial EPS was performed.• Spherical-shaped stabilized AgNPs and thin bio-film was observed in SEM and TEM.• UV–Vis spectroscopy and XRD spectral analysis revealed the confirmation of the EPS-stabilized AgNPs.• These AgNPs were shown to be highly thermo-stable up to 437.1 °C in TGA-DTA analysis.• EPS-stabilized AgNPs revealed application in textile for degradation of azo-dyes.

Biomonitoring along the Tropical Southern Indian Coast with Multiple Biomarkers

We assessed the spatial and temporal variations of pollution indicators and geochemical and trace metal parameters (23 in total) from water and sediment (144 samples) of three different eco-niches (beach, fishing harbor, and estuary) in larger coastal cities of southern India (Cuddalore and Pondicherry) for one year. A total of 120 marine Pseudomonas isolates were challenged against different concentrations of copper solutions and 10 different antibiotics in heavy metal and antibiotic resistance approaches, respectively. The study shows that 4.16% of the isolates could survive in 250 mM of copper; 70% were resistant to minimum concentrations. Strains were resistant (98.4%) to at least one antibiotic in Cuddalore compared to the Pondicherry (78.4%) region. Pollution index (PI) (0–14.55) and antibiotic resistance index (ARI) (0.05–0.10) ratio indicated that high bacterial and antibiotic loads were released into the coastal environment. The degree of trace metal contamination in sediments were calculated by enrichment factor (EF), contamination factor (CF), pollution load index (PLI), and geo-accumulation index (Igeo). Statistical parameters like two-way analysis of variance (ANOVA), correlation, factor analysis and scatter matrix tools were employed between the 23 parameters in order to find sources, pathways, disparities and interactions of environmental pollutants. It indicates that geochemical and biological parameters were not strongly associated with each other (except a few) and were affected by different sources. Factor analysis elucidated, ‘microbe–metal’ interaction (Factor 1–48.86%), ‘anthropogenic’ factor (Factor 2–13.23%) and ‘Pseudomonas–Cadmium’ factor (Factor 3–11.74%), respectively.

Marine Drugs Development and Social Implication

Marine sources have attracted much attention as potential sources for natural products over recent years. The future of the biopharmaceutical holds great promise due to the many compounds that have and will be isolated from marine sources. Marine organisms have long been recognized as a source of novel metabolites with applications in human disease therapy. The marine environment is a rich source of both biological and chemical diversity, where it has been reported that oceans contain nearly 300,000 described species, representing only a small percentage of the total number of species that have to be discovered. The ocean represents a rich resource for ever more novel compounds with great potential as pharmaceutical, nutritional supplements, cosmetics, agrichemicals and enzymes, where each of these marine bioproducts has a strong potential market value. The reasons for the strong showing of drug discovery from natural products can be attributed to the diverse structures, intricate carbon skeletons, and the ease that human bodies will accept these molecules with minimal manipulation. With new pressures from the public and governments around the world to develop products to combat diseases and infections commonly encountered, new chemical entities need to be found and developed.

Socio-ecological studies on a tropical coastal area in southern India

AbstractSocioeconomic status versus human health issues were studied during one year among coastal communities of southern India. Hydrochemical (16) and microbial parameters (9) were analyzed, and the results were represented by using correlation coefficient and principal component analysis (PCA). Bacteriological populations were higher in this order TVC > TC > VLO > VC > TS > FC > FS > SA, and antibiotic resistance to β-lactams (amoxicillin, ampicillin, methicillin, and penicillin-G) was found against Salmonella sp. (52%), Vibrio sp. (49%), E. coli (47.5%), and Shigella sp. (40%). According to our observational epidemiological survey, drinking water usage on people by municipal supplies accounted for 48% and groundwater sources for 52% of the demand. Open defecation accounted for 85.9%, wrecked latrines contributed with 10.4%, and the possibility of hygienic sanitary usage was available only to 3.7%. Average infection rates of male adult patients accounted for 29%, compared to female (12%) and children (8%) suggesting for the implementation of an effective child care program and national health mission.

Multivariate drug resistance and microbial risk assessment in tropical coastal communities

ABSTRACT Multivariate water quality parameters and statistical analysis were used to evaluate the factors controlling coastal drinking water quality and associated health risks among fisherfolks. Multidrug-resistant strains noticed in 400 isolates show 62% Salmonella; 53% Shigella sp.; 48% E. coli; and 36% Vibrio sp. in groundwater sample. In component analysis seawater intrusion, redox reaction, anthropogenic pollution, and weather factors were responsible for more than 93.3% in postmonsoon and 89.4% in summer season, respectively, for Cumulative %. In epidemiology study, 66% and 76% of municipally supplied drinking water were used in Pondicherry and Rameshwaram, respectively, compared to the amount of groundwater (34% and 20%) used in the study area. Similarly, Pondicherry and Rameshwaram areas recorded open defecation instances of 94% and 82%, respectively where less than 5% of the population used hygienic sanitation as part of the Clean India Mission in rural areas.