Identification and characterization of virulent Aeromonas hydrophila Ah17 from infected Channa striata in river Cauvery and in vitro evaluation of shrimp chitosan.

Aeromonas hydrophila, an inhabitant in the aquatic ecosystem is considered as an important foodborne bacterial zoonotic pathogen in aquaculture. The present study aimed to identify virulent A. hydrophila from naturally infected Channa striata in river Cauvery and in vitro evaluation of shrimp chitosan. Rimler Shotts (RS) and blood agar medium identified the presence of pathogenic Aeromonas sp. from the infected C. striata. A. hydrophila Ah17 was identified using 16S rRNA nucleotide sequence. Extracellular enzymes such as amylase, lipase, and protease were screened in A. hydrophila Ah17. Antibiotic susceptibility tests showed A. hydrophila Ah17 was highly resistant against ß-lactam, glycopeptide, macrolides, phosphonic, fucidin, and oxazolidinone classes of antibiotics. Virulent genes such as hemolysin (aer and hly), heat-labile enterotoxin (act), cytotonic heat-stable enterotoxin (ast), elastase (ahyB), and lipase (lip) were identified. Growth and the viable cell population of virulent A. hydrophila Ah17 were significantly reduced in a dose-dependent manner against shrimp chitosan (CHS) from Penaeus indicus (P. indicus). Thus, the present study isolated virulent A. hydrophila Ah17 from the environmental source and characterized in vitro with shrimp chitosan.

Influence of anti-inflammatory irrigant on substance P expression for single-visit root canal treatment of teeth with irreversible pulpitis.

One of the main objectives of root canal treatment is to alleviate the pain associated with irreversibly inflamed pulps. However, some patients may have moderate to severe pain following treatment. The aim of this study was to compare and assess the effect of ketorolac tromethamine on substance P expression in the pulp and periapical tissues when used as a root canal irrigant for single-visit root canal treatment in teeth with irreversible pulpitis. Thirty-six patients were randomly allotted to three irrigant groups - saline (n = 14), 3% sodium hypochlorite (n = 11) and ketorolac tromethamine (n = 11). Pulp blood samples (S1) were collected on gaining access to the pulp, and periapical blood samples (S2) were collected after root canal preparation. Quantification of substance P was done by ELISA test. The ketorolac tromethamine group had greater reduction in substance P expression (S2). Post-operative pain levels were not significantly influenced by the different root canal irrigants.

Influence of different irrigants on substance P and IL-8 expression for single visit root canal treatment in acute irreversible pulpitis.

The aim of this study was to assess the influence of ketorolac tromethamine and dexamethasone on substance P and IL-8 expression when used as a root canal irrigant for single visit root canal treatment for acute irreversible pulpitis. A total of 42 patients with pain due to acute irreversible pulpitis in carious premolar and molar teeth were included in this study. The four irrigation groups were as follows: saline (n = 11), 3% sodium hypochlorite (n = 11), ketorolac tromethamine (n = 10) and dexamethasone (n = 10). Blood samples S1 and S2 were collected upon access opening and after canal preparation, respectively. Quantification of substance P and IL-8 were done using ELISA test. Post-operative pain was assessed by questioning the patients. The difference between S1 and S2 sample values for the four different irrigant groups was not significant. The sodium hypochlorite group had a higher mean expression of substance P and IL-8 values. Dexamethasone irrigation was more effective in controlling post-operative pain.

Determination of lethal dose of Aeromonas hydrophila Ah17 strain in snake head fish Channa striata.

Aeromonas hydrophila is a major bacterial fish pathogen which causes economic losses in the aquaculture. The study determined the Letha Dose (LD50-96h) of A. hydrophila Ah17 strain (isolated from EUS infected Channa striata) in C. striata. C. striata were challenged with three different concentration of A. hydrophila Ah17 strain 1.0 × 107, 1.0 × 108, 1.0 × 109 CFU/mL. The LD50-96h values were found to be 4.1 × 108 CFU/mL. Percentage of mortality was observed as 10%, 40% and 70% in 1.0 × 107, 1.0 × 108 and 1.0 × 109 CFU/mL respectively in challenged fish. Microbial load was calculated on muscle, kidney, liver and spleen with highest load was observed in muscle and lowest in kidney. Level of liver enzymes such as Aspartate aminotransferase (AST), Alanine Aminotransferase (ALT), and Alkaline Phosphatase (ALP) were increased compared to control fish. Level of mRNA expression of antioxidant genes such as Catalase (cat), Manganese Superoxide Dismutase (MnSOD), Glutathione Peroxidase (GPx) were high in liver tissue of all treated groups than control. Clinical signs were observed after intraperitoneal treatment of Ah17 in C. striata. Clinical signs such as lesions on the site of injection, imbalanced state, changes in the movement of pectoral fins, depigmentation on the tail of caudal fin and irregular lesions on the muscle region were observed. Thus the study concluded that, the LD50-96h value of A. hydrophila Ah17 strain was 4.1 × 108 CFU/mL and exhibited potential pathogenic effect upon experimental infection in snakehead murrel C. striata.