Thumbnail Image

Thesis

Browse

20221
Reset filters
Subject: Veterinary Public Health × Author: NARENDRA KUMAR, GONEPUDI × End date: 2024 × Start date: 2022 ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    IDENTIFICATION AND CHARACTERIZATION OF MOTILE AEROMONADS ISOLATED FROM FISH AND FISH POND WATER WITH SPECIAL EMPHASIS ON VIRULENT Aeromonas hydrophila
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2022-03) NARENDRA KUMAR, GONEPUDI; SRINIVASA RAO, T (MAJOR); BINDU KIRANMAYI, Ch; ASWANI KUMAR, K
    Motile aeromonads are one of the troublesome bacteria affecting the aquaculture industry by causing an assortment of diseases and also implicated in causing illness to humans by consumption of raw or improperly cooked fish, drinking contaminated water and contamination of wounds by water having aeromonads etc. The present study was intended to characterize Aeromonas spp. of fish, fish pond water and also human diarrhoeal origin with special emphasis to isolate and identify Virulent Aeromonas hydrophila (VAh) based on cultural and molecular techniques. A total of 330 samples comprising healthy and diseased fish, fish pond water and human diarrhoeal samples were analyzed for presence of Aeromonas spp. viz. A. veronii and A. hydrophila. Overall prevalence of genus Aeromonas was found to be 37.27% (123/330). Out of 123 Aeromonas isolates, m-PCR revealed 67 (54.47%) were to be A. veronii and seven (5.69%) were to be A. hydrophila. Out of 74 positive Aeromonas spp. isolated from different sources, highest prevalence of 56.75% (42/74) was found in healthy fish followed by diseased fish 25.67 (19/74), fish pond water 16.21% (12/74) and human diarrhoea 1.35% (1/74). Out of seven A. hydrophila isolates, three isolates were phenotypically positive for VAh based on inositol fermentation on M9I agar. Among 74 Aeromonas spp. isolates, the phenotypic virulence factors i.e. biofilm formation, gelatinase activity, DNase activity, caseinase activity, lipase activity and hemolysis were detected in 61(82.43%), 70 (94.59%), 69 (93.24%), 52 (70.27%), 48 (64.86) and 70 (94.59%) of the isolates, respectively. Out of 74 Aeromonas spp. isolates, 49 were positive for atleast one of the virulence genes. 49 Aeromonas spp. revealed the presence of virulence genes i.e act, ast, alt, ahyB, fla, lip, aer, ser, gcat and exu which were detected in 35 (47.29%), 9 (12.16%), 14 (18.91%), 15 (20.27%), 3 (4.05%), 26 (35.13), 16 (21.62%), 7 (9.45%), 16 (21.62%) and 12 (16.21%) of the isolates, respectively. Antibiogram profiling of 74 Aeromonas isolates unveiled a significant fraction of the Aeromonas isolates to be resistant towards ampicillin and novobiocin (100%) followed by vancomycin (71.62%) and erythromycin (54.05%). ESBL production was confirmed in 24 Aeromonas spp. isolates by both phenotypic and molecular methods and blaTEM was the predominant gene in 23 isolates and blaOXA gene was detected in only one isolate. A greater degree of heterogeneity was observed among 24 ESBL positive Aeromonas spp. isolated from different sources as revealed by presence of 24 genotypes each by ERIC and REP-PCR analysis. 19 different A. veronii and five A. hydrophila subtypes were differentiated by ERIC-PCR and REP-PCR. Genotyping of Aeromonas spp. by ERIC-PCR and REP-PCR was found to be highly significant since the discriminatory power >0.9 is considered as highly significant (1 for both ERIC –PCR and REP-PCR). Cluster analysis also revealed a great degree of homogeneity and heterogeneity among different isolates recovered from different sources thereby indicating that there is a chance of cross-contamination particularly in the fish markets.