Considering the emerging concern with the antimicrobial resistance (AMR) evolution, the study has been designed to identify the antibiotic resistance and virulence properties of culturable bacteria isolated from the diseased fish Etroplus suratensis. This has resulted in the purification of 18 morphologically distinct bacterial isolates which were identified by both biochemical and molecular methods. Antibiotic resistance analysis showed the resistance of these isolates to multiple antibiotics and remarkable evolution of AMR. Further screening for virulence factors confirmed five isolates to be positive for haemolytic activity, eight with caseinase, four with DNase, one with gelatinase and three with biofilm-forming properties. In addition to these, the isolates were subjected to PCR-based screening to detect the presence of genes coding for aerolysin and haemolysin. Results showed the presence aerolysin gene in the isolates ESS3.2, ESS3.8, ESI3.3 and ESS3.6, while haemolysin gene was observed to be present in ESG3.1 and ESI3.2. The observed results hence indicate the need for frequent monitoring of these properties among bacterial isolates from diverse environment especially those associated with edible fish.

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Lanthanum phosphate (LaPO4) belongs to the family of rare earth phosphates characterized as a fluorescence material. Europium ion is known for its orange –red fluorescence. In order to include orange –red fluorescence for pure white light generation we are doping LaPO4 with Eu3+. The crystalline planes are identified from the XRD pattern show that the particles have monoclinic structure with pure LaPO4. The addition of sodium ions to the LaPO4: Eu3+ sample it is found that the luminescence property gets increased. It is also found that reversal of the emission spectrum intensity takes place for the sodium doped sample which indicates that Eu3+ ions are located in a highly symmetric environment.