I am currently a Post doctoral fellow at CUSAT, India and a former fellow at Centre for Disease Dynamics Economics and Policy (CDDEP). I am a microbiologist and have been working in various aspects of antimicrobial resistance (AMR) for past 11 years. AMR has always been my prime area of interest right from the beginning of my research career. After realizing the gravity of AMR as a global issue I would like to further expand my knowledge in this area and contribute my best to combat this issue. I also have good communication skills (oral and writing) and currently have 28 publications (Total impact factor- 90, citations- 707, h-index 9).My Post doctoral work focuses on ‘Elucidating the potential transmission of Carbapenem-resistant Enterobacteriaceae, specifically Klebsiella pneumoniae harbouring mobile antibiotic resistance genes through seafoods to humans’. I am also working on ‘Global surveillance of AMR and hypervirulence in Klebsiella pneumoniae in LMICs by analysing whole-genome sequences from NCBI database based on in-silico approach’. My PhD was on 'genotyping, virulence characterization and survival kinetics of vibrio spp. From food and environmental sources along south west coast of india' from CUSAT, India. Address: India
Burgeoning human population and the resultant pressure on infrastructure to treat the wastes is r... more Burgeoning human population and the resultant pressure on infrastructure to treat the wastes is resulting in considerable organic pollution of coastal waters and estuaries. Partially treated and untreated sewage is released into the above natural waters along with its range of microflora besides other organic and inorganic pollutants. Sources of bacterial pathogens in the sewage vary from hospital wastewater, human dwellings, abattoirs, farm wastes, and animal production centers. Short generation time of prokaryotes coupled with their exceptional ability to do horizontal gene transfer (HGT) makes them the most successful form of life on earth. However, this has huge implications for human health as the antimicrobial resistance (AMR) determinants among them get exchanged at a rapid pace resulting in multidrug-resistant (MDR) pathogens. Infections caused by MDR pathogens are taking a serious toll on human life in both developed and developing countries, posing a nightmare to health au...
Low-temperature-tolerant microorganisms and their cold-active enzymes could be an innovative and ... more Low-temperature-tolerant microorganisms and their cold-active enzymes could be an innovative and invaluable tool in various industrial applications. In the present study, bacterial isolates from the sediment samples of Kongsfjord, Norwegian Arctic, were screened for β-galactosidase production. Among the isolates, KS25, KS85, KS60, and KS92 have shown good potential in β-galactosidase production at 20°C. 16SrRNA gene sequence analysis revealed the relatedness of the isolates to Enterobacter ludwigii. The optimum growth temperature of the isolate was 25°C. The isolate exhibited good growth and enzyme production at a temperature range of 15-35°C, pH 5-10. The isolate preferred yeast extract and lactose for the maximum growth and enzyme production at conditions of pH 7.0, temperature of 25°C, and agitation speed of 100 rpm. The growth and enzyme production was stimulated by Mn 2+ and Mg 2+ and strongly inhibited by Zn 2+ , Ni 2+ , and Cu +. β-Galactosidases with high specific activity at low temperatures are very beneficial in food industry to compensate the nutritional problem associated with lactose intolerance. The isolate exhibited a remarkable capability to utilize clarified whey, an industrial pollutant, for good biomass and enzyme yield and hence could be well employed in whey bioremediation.
In tropical shrimp farms, especially in traditional pokkali shrimp ponds, poor water quality mana... more In tropical shrimp farms, especially in traditional pokkali shrimp ponds, poor water quality management can lead to serious threats like heavy algal blooms and frequent disease outbreaks. An investigation regarding the frequent disease outbreaks in selected pokkali shrimp pond adjoining the Cochin backwaters has been conducted. Water quality parameters were analyzed during the study period. Results indicate a considerable fluctuation in the concentration of dissolved oxygen (DO) in the study in the shrimp farm where the algal bloom was observed. Poor water exchange along with nutrient loading from adjacent housing areas resulted in heavy algal bloom in the pond which led to hypoxic conditions in early morning and supersaturation of DO in the afternoon. It also led to considerably high alkaline pH. High levels of total ammonia nitrogen (TAN) were recorded in the sampling sites. Heavy algal bloom was observed throughout the study period in the selected pond especially in the summer. Anabaenopsis elenkinii and Merismopedia elagans which were the dominant species from the culture pond caused the bloom. Characterization and percentage distribution of bacteria present in the water and those associated with the algal blooms were carried out. The algae were found to support greater diversity of bacteria when compared to water. Pathogenic species like Aeromonas hydrophila and Vibrio parahaemolyticus were encountered in the study. Experimental challenge studies using Artemia as a model showed that the V. parahaemolyticus isolates were highly pathogenic. Hence, this study reveals how algal growth supports opportunistic pathogens in great diverse in a shrimp pond and causes frequent disease outbreaks under favourable conditions.
The present study aimed to evaluate the relative survival of pathogenic Vibrio parahaemolyticus s... more The present study aimed to evaluate the relative survival of pathogenic Vibrio parahaemolyticus strains isolated from two different sources, in a tropical estuary along the southwest coast of India. Microcosms studies were conducted under controlled laboratory conditions. Each microcosm was inoculated with ~107 CFU/ml of the bacterial culture. Two multi-drug resistant V. parahaemolyticus strains carrying the virulence genes (tdh and trh) were used. The survival pattern of the strains was compared by analysing the role of various biological factors on the removal of these pathogens in the estuarine environment and the effect of temperature (25°C, 30°C, 35°C) on their survival. Results highlighted that sediments of estuary provides a favourable environment for extended survival of the pathogen. The strain from food source had a selective advantage over the environmental source to survive better in the estuarine environments. The study revealed a significant difference in the survival ...
V. parahaemolyticus (68.1%), V. alginolyticus (18.1%), V. vulnificus (2%), V. cholerae (1%), V. h... more V. parahaemolyticus (68.1%), V. alginolyticus (18.1%), V. vulnificus (2%), V. cholerae (1%), V. harveyi (1%) and V. mimicus (1%) were detected. Overall percentage of incidence was highest in clams (84.2%) followed by shrimps (63.8%) and crabs (37.5%). When isolates were tested for their susceptibility to various antibiotics, highest incidence of antibiotic resistance was evident against ampicillin and colistin followed by amoxycillin, carbenicillin, ceftazidime and cephalothin and lowest against chloramphenicol, tetracycline and nalidixic acid. Multiple drug resistance was prevalent among the isolates. Results indicate that the various seafood markets at the retail level in Cochin are contaminated with potentially pathogenic Vibrio species. If they survive insufficient processing/cooking conditions they would have an impact on safety of processed/cooked ready-to-eat food.
The antibacterial activity of different solvent fractions of Chroococcus minutus, isolated from C... more The antibacterial activity of different solvent fractions of Chroococcus minutus, isolated from Cochin estuary against a variety of aquaculture and human pathogens were tested. The diethyl ether extract was effective against nine pathogens, especially the vibrios. V. parahaemolyticus showed the maximum zone of inhibition (3.3cm). The methanolic and ethanolic extracts could inhibit only few pathogens whereas aqueous, dimethyl sulfoxide and acetone extracts were least effective.
India remains as a top supplier of value-added seafoods to the global markets. Cochin is one of t... more India remains as a top supplier of value-added seafoods to the global markets. Cochin is one of the leading fishing ports in India contributing to country’s major seafood export. As part of risk assessment, we analyzed the prevalence of multi-drug resistant Vibrio parahaemolyticus; seafood borne gastroenteritis-causing pathogen, in shellfishes collected from major fish markets in Cochin. This bacterial species was initially isolated on Thiosulfate-citrate-bile salts-sucrose agar and HiCrome™ Vibrio agar, further confirmed by detection of V. parahaemolyticus species-specific toxR gene and by 16S r RNA sequencing. A total of 113 confirmed V. parahaemolyticus were recovered. Almost all the strains exhibited resistance towards three or more antibiotics (multiple-drug resistant) and harbored virulence related exoenzymes especially hemolysin (Kanagawa phenomenon); which is indeed a matter of concern. The multiple antibiotic resistance (MAR) index of the isolates ranged from 0.21 to 0.57. ...
Abstract Seasonal prevalence of faecal coliforms in Indian black clam (Villorita cyprinoides), se... more Abstract Seasonal prevalence of faecal coliforms in Indian black clam (Villorita cyprinoides), sediment and harvesting waters from shellfish harvesting areas along Cochin estuary was evaluated. Enumeration was done by 5 tube most probable number (MPN) method. High prevalence of faecal coliforms was observed in shellfish, sediment and harvesting waters during monsoon and post-monsoon seasons compared to pre-monsoon season. Escherichia coli was isolated and identified by biochemical methods and further confirmed by PCR based detection of uid A gene. A total 125 E. coli strains were isolated; out of which 99 (79.2%) could be serotyped and comprised of 17 diverse serotypes. Approximately 89.06% of the serotyped strains belonged to 5 different pathogenic serotypes. Enterotoxigenic strains were the most prevalent, followed by enterohaemorrhagic, uropathogenic, enteropathogenic and enteroinvasive strains. Enterohaemorrhagic E. coli O157 strains were isolated from shellfish and sediment samples (7.07%). Multiplex PCR analysis revealed the presence of shiga toxin genes ( stx 1 , stx 2), intimin (eae) gene and enterohemolysin gene (hlyA). The overall prevalence of toxigenic genes among the strains was 78.1%; in shellfish (84%), sediment (78.1%) and water (69%). Shiga toxin gene stx 2 , showed the highest prevalence (54.3%), followed by eae (36.2%), stx 1 (20%), and hlyA (6.7%) genes. To the best of our knowledge, the present study is the first report on the isolation of E. coli O157 from shellfish harvesting areas along the Indian coast. Higher levels of faecal contamination along with the presence of pathogenic E. coli may pose potential health hazards to the consumers.
Burgeoning human population and the resultant pressure on infrastructure to treat the wastes is r... more Burgeoning human population and the resultant pressure on infrastructure to treat the wastes is resulting in considerable organic pollution of coastal waters and estuaries. Partially treated and untreated sewage is released into the above natural waters along with its range of microflora besides other organic and inorganic pollutants. Sources of bacterial pathogens in the sewage vary from hospital wastewater, human dwellings, abattoirs, farm wastes, and animal production centers. Short generation time of prokaryotes coupled with their exceptional ability to do horizontal gene transfer (HGT) makes them the most successful form of life on earth. However, this has huge implications for human health as the antimicrobial resistance (AMR) determinants among them get exchanged at a rapid pace resulting in multidrug-resistant (MDR) pathogens. Infections caused by MDR pathogens are taking a serious toll on human life in both developed and developing countries, posing a nightmare to health au...
Low-temperature-tolerant microorganisms and their cold-active enzymes could be an innovative and ... more Low-temperature-tolerant microorganisms and their cold-active enzymes could be an innovative and invaluable tool in various industrial applications. In the present study, bacterial isolates from the sediment samples of Kongsfjord, Norwegian Arctic, were screened for β-galactosidase production. Among the isolates, KS25, KS85, KS60, and KS92 have shown good potential in β-galactosidase production at 20°C. 16SrRNA gene sequence analysis revealed the relatedness of the isolates to Enterobacter ludwigii. The optimum growth temperature of the isolate was 25°C. The isolate exhibited good growth and enzyme production at a temperature range of 15-35°C, pH 5-10. The isolate preferred yeast extract and lactose for the maximum growth and enzyme production at conditions of pH 7.0, temperature of 25°C, and agitation speed of 100 rpm. The growth and enzyme production was stimulated by Mn 2+ and Mg 2+ and strongly inhibited by Zn 2+ , Ni 2+ , and Cu +. β-Galactosidases with high specific activity at low temperatures are very beneficial in food industry to compensate the nutritional problem associated with lactose intolerance. The isolate exhibited a remarkable capability to utilize clarified whey, an industrial pollutant, for good biomass and enzyme yield and hence could be well employed in whey bioremediation.
In tropical shrimp farms, especially in traditional pokkali shrimp ponds, poor water quality mana... more In tropical shrimp farms, especially in traditional pokkali shrimp ponds, poor water quality management can lead to serious threats like heavy algal blooms and frequent disease outbreaks. An investigation regarding the frequent disease outbreaks in selected pokkali shrimp pond adjoining the Cochin backwaters has been conducted. Water quality parameters were analyzed during the study period. Results indicate a considerable fluctuation in the concentration of dissolved oxygen (DO) in the study in the shrimp farm where the algal bloom was observed. Poor water exchange along with nutrient loading from adjacent housing areas resulted in heavy algal bloom in the pond which led to hypoxic conditions in early morning and supersaturation of DO in the afternoon. It also led to considerably high alkaline pH. High levels of total ammonia nitrogen (TAN) were recorded in the sampling sites. Heavy algal bloom was observed throughout the study period in the selected pond especially in the summer. Anabaenopsis elenkinii and Merismopedia elagans which were the dominant species from the culture pond caused the bloom. Characterization and percentage distribution of bacteria present in the water and those associated with the algal blooms were carried out. The algae were found to support greater diversity of bacteria when compared to water. Pathogenic species like Aeromonas hydrophila and Vibrio parahaemolyticus were encountered in the study. Experimental challenge studies using Artemia as a model showed that the V. parahaemolyticus isolates were highly pathogenic. Hence, this study reveals how algal growth supports opportunistic pathogens in great diverse in a shrimp pond and causes frequent disease outbreaks under favourable conditions.
The present study aimed to evaluate the relative survival of pathogenic Vibrio parahaemolyticus s... more The present study aimed to evaluate the relative survival of pathogenic Vibrio parahaemolyticus strains isolated from two different sources, in a tropical estuary along the southwest coast of India. Microcosms studies were conducted under controlled laboratory conditions. Each microcosm was inoculated with ~107 CFU/ml of the bacterial culture. Two multi-drug resistant V. parahaemolyticus strains carrying the virulence genes (tdh and trh) were used. The survival pattern of the strains was compared by analysing the role of various biological factors on the removal of these pathogens in the estuarine environment and the effect of temperature (25°C, 30°C, 35°C) on their survival. Results highlighted that sediments of estuary provides a favourable environment for extended survival of the pathogen. The strain from food source had a selective advantage over the environmental source to survive better in the estuarine environments. The study revealed a significant difference in the survival ...
V. parahaemolyticus (68.1%), V. alginolyticus (18.1%), V. vulnificus (2%), V. cholerae (1%), V. h... more V. parahaemolyticus (68.1%), V. alginolyticus (18.1%), V. vulnificus (2%), V. cholerae (1%), V. harveyi (1%) and V. mimicus (1%) were detected. Overall percentage of incidence was highest in clams (84.2%) followed by shrimps (63.8%) and crabs (37.5%). When isolates were tested for their susceptibility to various antibiotics, highest incidence of antibiotic resistance was evident against ampicillin and colistin followed by amoxycillin, carbenicillin, ceftazidime and cephalothin and lowest against chloramphenicol, tetracycline and nalidixic acid. Multiple drug resistance was prevalent among the isolates. Results indicate that the various seafood markets at the retail level in Cochin are contaminated with potentially pathogenic Vibrio species. If they survive insufficient processing/cooking conditions they would have an impact on safety of processed/cooked ready-to-eat food.
The antibacterial activity of different solvent fractions of Chroococcus minutus, isolated from C... more The antibacterial activity of different solvent fractions of Chroococcus minutus, isolated from Cochin estuary against a variety of aquaculture and human pathogens were tested. The diethyl ether extract was effective against nine pathogens, especially the vibrios. V. parahaemolyticus showed the maximum zone of inhibition (3.3cm). The methanolic and ethanolic extracts could inhibit only few pathogens whereas aqueous, dimethyl sulfoxide and acetone extracts were least effective.
India remains as a top supplier of value-added seafoods to the global markets. Cochin is one of t... more India remains as a top supplier of value-added seafoods to the global markets. Cochin is one of the leading fishing ports in India contributing to country’s major seafood export. As part of risk assessment, we analyzed the prevalence of multi-drug resistant Vibrio parahaemolyticus; seafood borne gastroenteritis-causing pathogen, in shellfishes collected from major fish markets in Cochin. This bacterial species was initially isolated on Thiosulfate-citrate-bile salts-sucrose agar and HiCrome™ Vibrio agar, further confirmed by detection of V. parahaemolyticus species-specific toxR gene and by 16S r RNA sequencing. A total of 113 confirmed V. parahaemolyticus were recovered. Almost all the strains exhibited resistance towards three or more antibiotics (multiple-drug resistant) and harbored virulence related exoenzymes especially hemolysin (Kanagawa phenomenon); which is indeed a matter of concern. The multiple antibiotic resistance (MAR) index of the isolates ranged from 0.21 to 0.57. ...
Abstract Seasonal prevalence of faecal coliforms in Indian black clam (Villorita cyprinoides), se... more Abstract Seasonal prevalence of faecal coliforms in Indian black clam (Villorita cyprinoides), sediment and harvesting waters from shellfish harvesting areas along Cochin estuary was evaluated. Enumeration was done by 5 tube most probable number (MPN) method. High prevalence of faecal coliforms was observed in shellfish, sediment and harvesting waters during monsoon and post-monsoon seasons compared to pre-monsoon season. Escherichia coli was isolated and identified by biochemical methods and further confirmed by PCR based detection of uid A gene. A total 125 E. coli strains were isolated; out of which 99 (79.2%) could be serotyped and comprised of 17 diverse serotypes. Approximately 89.06% of the serotyped strains belonged to 5 different pathogenic serotypes. Enterotoxigenic strains were the most prevalent, followed by enterohaemorrhagic, uropathogenic, enteropathogenic and enteroinvasive strains. Enterohaemorrhagic E. coli O157 strains were isolated from shellfish and sediment samples (7.07%). Multiplex PCR analysis revealed the presence of shiga toxin genes ( stx 1 , stx 2), intimin (eae) gene and enterohemolysin gene (hlyA). The overall prevalence of toxigenic genes among the strains was 78.1%; in shellfish (84%), sediment (78.1%) and water (69%). Shiga toxin gene stx 2 , showed the highest prevalence (54.3%), followed by eae (36.2%), stx 1 (20%), and hlyA (6.7%) genes. To the best of our knowledge, the present study is the first report on the isolation of E. coli O157 from shellfish harvesting areas along the Indian coast. Higher levels of faecal contamination along with the presence of pathogenic E. coli may pose potential health hazards to the consumers.
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