Rathinam Arthur James

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.

DNA/RNA binding and anticancer/antimicrobial activities of polymer-copper(II) complexes.

Water soluble polymer-copper(II) complexes with various degrees of coordination in the polymer chain were synthesized and characterized by elemental analysis, IR, UV-visible and EPR spectra. The DNA/RNA binding behavior of these polymer-copper(II) complexes was examined by UV-visible absorption, emission and circular dichroism spectroscopic methods, and cyclic voltammetry techniques. The binding of the polymer-copper(II) complexes with DNA/RNA was mainly through intercalation but some amount of electrostatic interaction was also observed. This binding capacity increased with the degree of coordination of the complexes. The polymer-copper(II) complex having the highest degree of coordination was subjected to analysis of cytotoxic and antimicrobial properties. The cytotoxicity study indicated that the polymer-copper(II) complexes affected the viability of MCF-7 mammary carcinoma cells, and the cells responded to the treatment with mostly through apoptosis although a few cells succumbed to necrosis. The antimicrobial screening showed activity against some human pathogens.

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.

Multi metal assessment on biofilm formation in offshore environment

Eight metal and non-metal coupons were exposed to seawater in offshore platform laboratory on biofilm formation in seven days of every month interval time for one year period. Among metal coupons, the highest mean heterotrophic biofilm bacteria population (HBBP) ranges were observed in mild steel (MS) coupon (33.03 to 40.00 [×104] CFUscm-2) and lowest in copper (Cu) coupon (3.0 to 5.1 [×104] CFUscm-2). Non-metal coupons show, highest mean HBBP ranges in glass (GL) coupon (29.6 to 66.0 [×104] CFUscm-2) and lowest in polyvinyl chloride (PVC) coupon (34.4 to 52.5 [×104] CFUscm-2). Within the studied coupons, high HBBP level was witnessed in GL and simultaneously low in Cu due to its toxic leaching product of Cu2O. Gram-positive bacterial deposit show dominated trend in all coupons with increasing order of Cu>SS>MS>PVC>GL>Cu-Ni 70/30>Cu-Ni 90/10>Br and Gram-negative show different in the order of Br>Cu-Ni 90/10>Cu-Ni 70/30>GL>PVC>MS>SS>Cu, respectively. The 16S rDNA sequence confirmed, heterotrophic biofilm Bacillus sp. (Gram-positive) were dominated in all coupons for all months.

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.

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.

Bioinspired Polymer Metal Complex Conjugates: [Co(NN)2Cl]2+ and [Cu(NN)2]2+ Moieties Graft in the Same Branched Polyethyleneimine (BPEI)-Synthesis, Biophysical and Biological Studies

AbstractThe hydrophilic pendant type polymer bound (Co3+ and Cu2+) complexes conjugates were synthesised and characterized by spectro-chemical analysis. The key features of these complexes are highly stable, redox active and show a quasi-reversible in the cyclic voltammetry response. The molecular interaction of these complexes with calf-thymus DNA were investigated using spectroscopic techniques such as absorption, emission, cyclic voltammetry and circular dichroism. The antimicrobial susceptibility of few bacterial and fungi strains were determined by the zone of inhibition method. The cell proliferation and mode of cell death induced by polymer-metal complexes in MDA-MB-231 breast cancer cell were determined using activated WST-1 assay, caspase-3 and propidium iodide labeling assay adopting flow cytometry.Graphical AbstractLeft Mode of cell death dual apoptotic pathways of the Co–BPEI–Cu injected cells. Right: photographic image of the Co–BPEI–Cu 1–4 dissolved in water.