Search

The present study was aimed to detect the plasmid profile, the role of plasmid associated multiple antibiotic resistance of Vibrios isolated from coastal waters of Kerala. The isolated plasmids from antibiotic resistant Vibrios were tested for the presence of integrons using polymerase chain reaction (PCR) to elucidate the presence of plasmid borne integron, a key element in horizontal gene transfer. 100 isolates of Vibrios from water samples of shrimp farms and coastal landing sites were tested for the antibiogram profile to 22 antibiotics and the presence of the plasmids. Antibiotic resistance studies revealed that 78% were expressing multiple antibiotic resistance (MAR), defined as the isolates having resistant to more than three resistance determinants. The levels of resistance exhibited by isolates to specific antibiotics vary between 94 % and 6%. In the plasmid profiling test, only 17 isolates (21%) harbored plasmid DNA which ranged in size from 1.4 to 25 kb, separating the isolates into various plasmid profiles. Interestingly it was observed from the plasmid profiling that 11 strains among them had a single plasmid, 4 strains were with two plasmids and one each of having three and four plasmids. The role of native plasmids in antibiotic resistance in Vibrios was confirmed by isolation and transformation of the plasmids in E.coli DH5a, followed by antibiotic resistance assay. Both the plasmids and the associated antibiotic resistance of selected isolates could be transferred to a recipient by transformation and conjugation. The study demonstrates the plasmid-mediated drug resistance as a contributor to the antibiotic resistance in Vibrios of the aquatic system and their ability to disseminate the resistance by means of transformation, conjugation and by horizontal gene transfer element like integrons. Antibiotic resistance marker and its location were confirmed from the resistant plasmids from Vibrio isolates by using curing protocols. As in many developing countries, antimicrobial resistance epidemiology is still in the infancy stage in the locality of the study. To our knowledge, there are no reports available on the plasmid mediated multiple antibiotic resistance in Vibrio isolates from coastal waters of Kerala and our study on plasmid profiling will provide a current baseline profile of plasmid mediated resistance of Vibrios from coastal waters in Kerala and thereby will provide a significant insight about Indian scenario. [ABSTRACT FROM AUTHOR]

Vibrio vulnificus , Vibrio parahaemolyticus and Vibrio harveyi are the causative agents of the most severe diseases of marine and brackish aquaculture systems. These are also associated with serious ailments in humans. The present paper unravels the virulence features/genes and antimicrobial resistance (AMR) phenotypes/genes of these Vibrio spp. isolated from natural disease outbreaks of marine/estuarine fishes of India for the first time. Results on virulence features showed that V. vulnificus infected fish can pose public health risk. While, it has been found clinically that V. parahaemolyticus without tdh and trh genes are pathogenic to fish, even though they are reported to be, not associated with human diseases. It was significant to note that virulence features of V. harveyi were induced at increased salinity. Analysis based on the percentage prevalence of susceptible isolates and variation coefficient of zone diameters categorized 17 antibiotics in terms of their efficiency against each fish pathogenic species. Multiple antibiotic resistance index (MARi) of the isolates ranged between 0.058 and 0.47. Results on MARi and percentage of multidrug resistance strains indicated that >50% of the isolates were from low antibiotic usage area. The study generated tetH sequence from V. parahaemolyticus for the first time, and the sequence revealed high identity to that of clinical strains. Presence of tetB/ tetH gene was identified as the predictor for the resistance against the first generation tetracycline, the most commonly used antibiotic against Vibrio spp. in aquaculture practices. The data on associations between AMR features predicted certain cross-resistance between antimicrobials within Vibrio spp. Altogether, the paper serves as the baseline for epizootic tracking of public health significant vibrios from diseased fishes, to devise practical guidelines for antibiotic use and to formulate efficient control measures against three Vibrio spp. in aquaculture, targeting final applications in the implementation of national green and healthy aquaculture practices. • Helps to devise control measures against three pathogens of aquaculture practices. • Data for epizootic tracking of public health important vibrios from diseased fishes. • First report on antibiotic categorization based on activity against fish pathogens. • Shows predictor genes for 1st generation tetracycline resistance in fish pathogens. [ABSTRACT FROM AUTHOR]

Coastal water quality assessment is important to maintain a healthy environment for various uses including fisheries and recreation. Microbial populations are used as biological indicators of contamination to monitor water quality and are considered by the government to be one of the critical features for issuing safety guidelines. Different bacterial groups (pathogenic, vibrio and faecal) from five major recreational beaches of Chennai, India, were monitored for the assessment of coastal water quality. Faecal coliforms (FC) were high at all the beaches, with up to 4.2 × 10 5  CFU/mL and exceeding the normal standard limits of 100 CFU/100 mL set by the Central Pollution Control Board (CPCB) of India. Rainfall was found to have a role in the variability and distribution of indicator and pathogenic bacteria. The seasonal dry period witnessed elevated FC, while dilution in the wet period reduced Escherichia coli-like organisms (ECLO). High microbial counts were detected near the beach situated close to the river mouth, mainly due to discharges of untreated domestic sewage and industrial wastes. Similarly, the biological oxygen demand (BOD) was also high, 0.32 to 10.32 mg/L. Dissolved inorganic nitrogen (DIN) ranged from 2.21 to 134.53 μmol/L and inorganic phosphate (IP) ranged from 0 to 57.53 μmol/L. These values indicated the presence of significant untreated sewage in the coastal water. This study revealed that Chennai coastal waters carry high levels of faecal and pathogenic bacteria, detrimental for recreational and other contact activities. The quantitative and qualitative analyses will be useful for modelling and prediction of coastal water quality and management of other recreational beaches in India.